Withdrawal of alcohol promotes regression while continued alcohol intake promotes persistence of LPS-induced pancreatic injury in alcohol-fed rats

CREB activation drives acinar to ductal reprogramming and promote pancreatic cancer progression in animal models of alcoholic chronic pancreatitis

BACKGROUND AND AIMS

In vivo induction of alcoholic chronic pancreatitis (ACP) causes significant acinar damage, increased fibroinflammatory response, and heightened activation of cyclic response element binding protein 1 (CREB) when compared with alcohol (A) or chronic pancreatitis (CP) mediated pancreatic damage. However, the study elucidating the cooperative interaction between CREB and the oncogenic Kras G12D/+ (Kras*) in promoting pancreatic cancer progression with ACP remains unexplored.

METHODS

Experimental ACP induction was established in multiple mouse models, followed by euthanization of the animals at various time intervals during the recovery periods. Tumor latency was determined in these mice cohorts. Here, we established CREB deletion (Creb fl/fl ) in Ptf1a CreERTM/+ ;LSL-Kras G12D+/-(KC) genetic mouse models (KCC-/-). Western blot, phosphokinase array, and qPCR were used to analyze the pancreata of Ptf1a CreERTM+/-, KC and KCC -/- mice. The pancreata of ACP-induced KC mice were subjected to single-cell RNA sequencing (scRNAseq). Further studies involved conducting lineage tracing and acinar cell explant cultures.

RESULTS

ACP induction in KC mice had detrimental effects on the pancreatic damage repair mechanism. The persistent existence of acinar cell-derived ductal lesions demonstrated a prolonged state of hyperactivated CREB. Persistent CREB activation leads to acinar cell reprogramming and increased pro-fibrotic inflammation in KC mice. Acinar-specific Creb ablation reduced advanced PanINs lesions, hindered tumor progression, and restored acinar cell function in ACP-induced mouse models.

CONCLUSIONS

Our findings demonstrate that CREB cooperates with Kras* to perpetuate an irreversible ADM and PanIN formation. Moreover, CREB sustains oncogenic activity to promote the progression of premalignant lesions toward cancer in the presence of ACP.

Activation and Regulation of Pancreatic Stellate Cells in Chronic Pancreatic Fibrosis: A Potential Therapeutic Approach for Chronic Pancreatitis

In the complex progression of fibrosis in chronic pancreatitis, pancreatic stellate cells (PSCs) emerge as central figures. These cells, initially in a dormant state characterized by the storage of vitamin A lipid droplets within the chronic pancreatitis microenvironment, undergo a profound transformation into an activated state, typified by the secretion of an abundant extracellular matrix, including α-smooth muscle actin (α-SMA). This review delves into the myriad factors that trigger PSC activation within the context of chronic pancreatitis. These factors encompass alcohol, cigarette smoke, hyperglycemia, mechanical stress, acinar cell injury, and inflammatory cells, with a focus on elucidating their underlying mechanisms. Additionally, we explore the regulatory factors that play significant roles during PSC activation, such as TGF-β, CTGF, IL-10, PDGF, among others. The investigation into these regulatory factors and pathways involved in PSC activation holds promise in identifying potential therapeutic targets for ameliorating fibrosis in chronic pancreatitis. We provide a summary of recent research findings pertaining to the modulation of PSC activation, covering essential genes and innovative regulatory mediators designed to counteract PSC activation. We anticipate that this research will stimulate further insights into PSC activation and the mechanisms of pancreatic fibrosis, ultimately leading to the discovery of groundbreaking therapies targeting cellular and molecular responses within these processes.

Immune cell infiltration in the pancreas of type 1, type 2 and type 3c diabetes

The different types of diabetes differ in disease pathogenesis but share the impairment or loss of β-cell function leading to chronic hyperglycaemia. While immune cells are present throughout the whole pancreas in normality, their number and activation is increased in diabetes. Different patterns and composition of inflammation could be observed in type 1, type 2 and type 3c diabetes. Immune cells, pancreatic stellate cells and fibrosis were present in the islet microenvironment and could add to β-cell dysfunction and therefore development and progression of diabetes. First studies investigating the use of anti-inflammatory drugs demonstrate their ability to rescue remaining β-cell function and their potential benefit in diabetes treatment. This article provides an overview of immune cell infiltrates in different types of diabetes, highlights the knowledge of their impact on β-cell function and introduces the potential of immunomodulatory strategies.

Urolithin A attenuates severity of chronic pancreatitis associated with continued alcohol intake by inhibiting PI3K/AKT/mTOR signaling

Heavy alcohol consumption is the dominant risk factor for chronic pancreatitis (CP); however, treatment and prevention strategies for alcoholic chronic pancreatitis (ACP) remains limited. The present study demonstrates that ACP induction in C57BL/6 mice causes significant acinar cell injury, pancreatic stellate cell (PSC) activation, exocrine function insufficiency, and an increased fibroinflammatory response when compared with alcohol or CP alone. Although the withdrawal of alcohol during ACP recovery led to reversion of pancreatic damage, continued alcohol consumption with established ACP perpetuated pancreatic injury. In addition, phosphokinase array and Western blot analysis of ACP-induced mice pancreata revealed activation of the phosphatidylinositol 3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and cyclic AMP response element binding protein (CREB) signaling pathways possibly orchestrating the fibroinflammatory program of ACP pathogenesis. Mice treated with urolithin A (Uro A, a gut-derived microbial metabolite) in the setting of ACP with continued alcohol intake (during the recovery period) showed suppression of AKT and P70S6K activation, and acinar damage was significantly reduced with a parallel reduction in pancreas-infiltrating macrophages and proinflammatory cytokine accumulation. These results collectively provide mechanistic insight into the impact of Uro A on attenuation of ACP severity through suppression of PI3K/AKT/mTOR signaling pathways and can be a useful therapeutic approach in patients with ACP with continuous alcohol intake.NEW & NOTEWORTHY Our novel findings presented here demonstrate the utility of Uro A as an effective therapeutic agent in attenuating alcoholic chronic pancreatitis (ACP) severity with alcohol continuation after established disease, through suppression of the PI3K/AKT/mTOR signaling pathway.

St13 protects against disordered acinar cell arachidonic acid pathway in chronic pancreatitis

BACKGROUND

Early diagnosis and treatment of chronic pancreatitis (CP) are limited. In this study, St13, a co-chaperone protein, was investigated whether it constituted a novel regulatory target in CP. Meanwhile, we evaluated the value of micro-PET/CT in the early diagnosis of CP.

METHODS

Data from healthy control individuals and patients with alcoholic CP (ACP) or non-ACP (nACP) were analysed. PRSS1 transgenic mice (PRSS1^Tg) were treated with ethanol or caerulein to mimic the development of ACP or nACP, respectively. Pancreatic lipid metabolite profiling was performed in human and PRSS1^Tg model mice. The potential functions of St13 were investigated by crossing PRSS1^Tg mice with St13^-/- mice via immunoprecipitation and lipid metabolomics. Micro-PET/CT was performed to evaluate pancreatic morphology and fibrosis in CP model.

RESULTS

The arachidonic acid (AA) pathway ranked the most commonly dysregulated lipid pathway in ACP and nACP in human and mice. Knockout of St13 exacerbated fatty replacement and fibrosis in CP model. Sdf2l1 was identified as a binding partner of St13 as it stabilizes the IRE1α-XBP1s signalling pathway, which regulates COX-2, an important component in AA metabolism. Micro-PET/CT with ⁶⁸Ga-FAPI-04 was useful for evaluating pancreatic morphology and fibrosis in CP model mice 2 weeks after modelling.

CONCLUSION

St13 is functionally activated in acinar cells and protects against the cellular characteristics of CP by binding Sdf2l1, regulating AA pathway. ⁶⁸Ga-FAPI-04 PET/CT may be a very valuable approach for the early diagnosis of CP. These findings thus provide novel insights into both diagnosis and treatment of CP.

Effect of Placenta-Derived Mesenchymal Stromal Cells Conditioned Media on an LPS-Induced Mouse Model of Preeclampsia

We tested the pro-angiogenic and anti-inflammatory effects of human placenta-derived mesenchymal stromal cells (hPDMSCs)-derived conditioned media (CM) on a mouse model of preeclampsia (PE), a severe human pregnancy-related syndrome characterized by maternal hypertension, proteinuria, endothelial damage, inflammation, often associated with fetal growth restriction (FGR). At d11 of pregnancy, PE was induced in pregnant C57BL/6N mice by bacterial lipopolysaccharide (LPS) intravenous injection. At d12, 300 μL of unconditioned media (control group) or 300 μL PDMSCs-CM (CM group) were injected. Maternal systolic blood pressure was measured from 9 to 18 days of pregnancy. Urine protein content were analyzed at days 12, 13, and 17 of pregnancy. At d19, mice were sacrificed. Number of fetuses, FGR, fetal reabsorption, and placental weight were evaluated. Placentae were analyzed for sFlt-1, IL-6, and TNF-α gene and protein expressions. No FGR and/or reabsorbed fetuses were delivered by PDMSCs-CM-treated PE mice, while five FGR fetuses were found in the control group accompanied by a lower placental weight. PDMSCs-CM injection significantly decreased maternal systolic blood pressure, proteinuria, sFlt-1, IL-6, and TNF-α levels in PE mice. Our data indicate that hPDMSCs-CM can reverse PE-like features during pregnancy, suggesting a therapeutic role for hPDMSCs for the treatment of preeclampsia.

Targeting Endoplasmic Reticulum Stress as an Effective Treatment for Alcoholic Pancreatitis

Pancreatitis and alcoholic pancreatitis are serious health concerns with an urgent need for effective treatment strategies. Alcohol is a known etiological factor for pancreatitis, including acute pancreatitis (AP) and chronic pancreatitis (CP). Excessive alcohol consumption induces many pathological stress responses; of particular note is endoplasmic reticulum (ER) stress and adaptive unfolded protein response (UPR). ER stress results from the accumulation of unfolded/misfolded protein in the ER and is implicated in the pathogenesis of alcoholic pancreatitis. Here, we summarize the possible mechanisms by which ER stress contributes to alcoholic pancreatitis. We also discuss potential approaches targeting ER stress and UPR in developing novel therapeutic strategies for the disease.

Ethanol exposure of human pancreatic normal ductal epithelial cells induces EMT phenotype and enhances pancreatic cancer development in KC (Pdx1-Cre and LSL-KrasG12D ) mice

Alcohol is a risk factor for pancreatic cancer. However, the molecular mechanism by which chronic alcohol consumption influences pancreatic cancer development is not well understood. We have recently demonstrated that chronic ethanol exposure of pancreatic normal ductal epithelial cells (HPNE) induces cellular transformation by generating cancer stem cells (CSCs). Here, we examined whether chronic ethanol treatment induces epithelial–mesenchymal transition in HPNE cells and promotes pancreatic cancer development in KC (Pdx1‐Cre, and LSL‐Kras^G12D) mice. Our data demonstrate that chronic ethanol exposure of HPNE cells induces SATB2 gene and those cells became highly motile. Ethanol treatment of HPNE cells results in downregulation of E‐Cadherin and upregulation of N‐Cadherin, Snail, Slug, Zeb1, Nanog and BMI‐1. Suppression of SATB2 expression in ethanol‐transformed HPNE cells inhibits EMT phenotypes. KC mice fed with an ethanol‐containing diet show enhanced pancreatic cancer growth and development than those fed with a control diet. Pancreas isolated from KC mice fed with an ethanol‐containing diet show higher expression of stem cell markers (CD133, CD44, CD24), pluripotency‐maintaining factors (cMyc, KLF4, SOX‐2, and Oct‐4), N‐Cadherin, EMT‐transcription factors (Snail, Slug, and Zeb1), and lower expression of E‐cadherin than those isolated from mice fed with a control diet. Furthermore, pancreas isolated from KC mice fed with an ethanol‐containing diet show higher expression of inflammatory cytokines (TNF‐α, IL‐6, and IL‐8) and PTGS‐2 (COX‐2) gene than those isolated from mice fed with a control diet. These data suggest that chronic alcohol consumption may contribute to pancreatic cancer development by generating inflammatory signals and CSCs.

NF-κB and Pancreatic Cancer; Chapter and Verse

Pancreatic Ductal Adenocarcinoma (PDAC) is one of the world's most lethal cancers. An increase in occurrence, coupled with, presently limited treatment options, necessitates the pursuit of new therapeutic approaches. Many human cancers, including PDAC are initiated by unresolved inflammation. The transcription factor NF-κB coordinates many signals that drive cellular activation and proliferation during immunity but also those involved in inflammation and autophagy which may instigate tumorigenesis. It is not surprising therefore, that activation of canonical and non-canonical NF-κB pathways is increasingly recognized as an important driver of pancreatic injury, progression to tumorigenesis and drug resistance. Paradoxically, NF-κB dysregulation has also been shown to inhibit pancreatic inflammation and pancreatic cancer, depending on the context. A pro-oncogenic or pro-suppressive role for individual components of the NF-κB pathway appears to be cell type, microenvironment and even stage dependent. This review provides an outline of NF-κB signaling, focusing on the role of the various NF-κB family members in the evolving inflammatory PDAC microenvironment. Finally, we discuss pharmacological control of NF-κB to curb inflammation, focussing on novel anti-cancer agents which reinstate the process of cancer cell death, the Smac mimetics and their pre-clinical and early clinical trials.

Molecular mechanisms of pancreatic myofibroblast activation in chronic pancreatitis and pancreatic ductal adenocarcinoma

Pancreatic fibrosis (PF) is an essential component of the pathobiology of chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC). Activated pancreatic myofibroblasts (PMFs) are crucial for the deposition of the extracellular matrix, and fibrotic reaction in response to sustained signaling. Consequently, understanding of the molecular mechanisms of PMF activation is not only critical for understanding CP and PDAC biology but is also a fertile area of research for the development of novel therapeutic strategies for pancreatic pathologies. This review analyzes the key signaling events that drive PMF activation including, initiating signals from transforming growth factor-β1, platelet derived growth factor, as well as other microenvironmental cues, like hypoxia and extracellular matrix rigidity. Further, we discussed the intracellular signal events contributing to PMF activation, and crosstalk with different components of tumor microenvironment. Additionally, association of epidemiologically established risk factors for CP and PDAC, like alcohol intake, tobacco exposure, and metabolic factors with PMF activation, is discussed to comprehend the role of lifestyle factors on pancreatic pathologies. Overall, this analysis provides insight into the biology of PMF activation and highlights salient features of this process, which offer promising therapeutic targets.

Distinct Murine Pancreatic Transcriptomic Signatures during Chronic Pancreatitis Recovery

We have previously demonstrated that the pancreas can recover from chronic pancreatitis (CP) lesions in the cerulein-induced mouse model. To explore how pancreatic recovery is achieved at the molecular level, we used RNA-sequencing (seq) and profiled transcriptomes during CP transition to recovery. CP was induced by intraperitoneally injecting cerulein in C57BL/6 mice. Time-matched controls (CON) were given normal saline. Pancreata were harvested from mice 4 days after the final injections (designated as CP and CON) or 4 weeks after the final injections (designated as CP recovery (CPR) and control recovery (CONR)). Pancreatic RNAs were extracted for RNA-seq and quantitative (q) PCR validation. Using RNA-seq, we identified a total of 3,600 differentially expressed genes (DEGs) in CP versus CON and 166 DEGs in CPR versus CONR. There are 132 DEGs overlapped between CP and CPR and 34 DEGs unique to CPR. A number of selected pancreatic fibrosis-relevant DEGs were validated by qPCR. The top 20 gene sets enriched from DEGs shared between CP and CPR are relevant to extracellular matrix and cancer biology, whereas the top 10 gene sets enriched from DEGs specific to CPR are pertinent to DNA methylation and specific signaling pathways. In conclusion, we identified a distinct set of DEGs in association with extracellular matrix and cancer cell activities to contrast CP and CPR. Once during ongoing CP recovery, DEGs relevant to DNA methylation and specific signaling pathways were induced to express. The DEGs shared between CP and CPR and the DEGs specific to CPR may serve as the unique transcriptomic signatures and biomarkers for determining CP recovery and monitoring potential therapeutic responses at the molecular level to reflect pancreatic histological resolution.

Interleukin-6 participates in human pancreatic stellate cell activation and collagen I production via TGF-β1/Smad pathway

Pancreatic stellate cells (PSCs) play a key role in fibrogenesis during alcoholic chronic pancreatitis (ACP). Transforming growth factor-β1 (TGF-β1) is a major regulator of PSC activation and extracellular matrix production. Interleukin-6 (IL-6) has shown to participate in TGF-β1 production and rat PSC activation. This study aimed to investigate whether IL-6 promotes human PSC activation and collagen 1(Col1) production through the TGF-β1/Smad pathway. Our results showed that the expression of IL-6 and IL-6R in activated PSCs and macrophages (Mφs) were enhanced in the pancreas of ACP compared to healthy controls and that the mRNA expression of IL-6, IL-6R, TGF-β1, α-SMA or Col1a1 were significantly increased in the pancreas of ACP, showing positive correlations between elevated IL-6 levels and either TGF-β1 or α-SMA or Col1a1 levels and between elevated TGF-β1 levels and α-SMA or Col1a1 levels. In in vitro studies, we identified that IL-6R expression or IL-6 and TGF-β1 secretions were significantly increased in, respectively, Mφs and PSCs by ethanol (EtOH) or lipopolysaccharide (LPS) stimulation while EtOH- or LPS-induced α-SMA or Col1a1 mRNA and protein production in PSCs were partially blocked by IL-6 antibody. IL-6-induced TGF-β1 production in PSCs was antagonized by si-IL-6R RNA or by an inhibitor of STAT3. Additionally, IL-6-promoted α-SMA or Col1a1 protein production was blocked by TGF-β1 antibody and IL-6-induced phosphorylation of Smad2/3 and transcription of α-SMA and Col1a1 mRNA were antagonized by si-TGF-β1 RNA. Our findings indicate that IL-6 contributes to PSC activation and Col1 production through up-regulation of TGF-β1/Smad2/3 pathway.

Prospect and clinical value of oxymatrine in prevention and treatment of pancreatic fibrosis

Studies have confirmed that pancreatic stellate cell activation is the central event in the initiation and development of pancreatic fibrosis (PF), but the specific mechanism of PF is still unknown, and there is no specific treatment for PF. Some basic studies have confirmed that oxymatrine (OMT) has a certain therapeutic effect on PF, but further research is needed. It can be predicted that OMT has a far-reaching research prospect and good clinical application value for the prevention and treatment of PF, and is also conducive to the better development and utilization of traditional Chinese herbal medicine radix sophorae flavescentis.

Alcohol and Smoking Mediated Modulations in Adaptive Immunity in Pancreatitis

Pancreatitis is a condition of pancreatic inflammation driven by injury to the pancreatic parenchyma. The extent of acinar insult, intensity, and type of immune response determines the severity of the disease. Smoking, alcohol and autoimmune pancreatitis are some of the predominant risk factors that increase the risk of pancreatitis by differentially influencing the adaptive immune system. The overall decrease in peripheral lymphocyte (T-, B- and (natural killer T-) NKT-cell) count and increased infiltration into the damaged pancreatic tissue highlight the contribution of adaptive immunity in the disease pathology. Smoking and alcohol modulate the responsiveness and apoptosis of T- and B-cells during pancreatic insult. Acute pancreatitis worsens with smoking and alcohol, leading to the development of systemic inflammatory response syndrome and compensatory anti-inflammatory response syndrome, suggesting the critical role of adaptive immunity in fatal outcomes such as multiple organ dysfunction. The presence of CD4⁺ and CD8⁺ T-lymphocytes and perforin-expressing cells in the fibrotic tissue in chronic pancreatitis modulate the severity of the disease. Due to their important role in altering the severity of the disease, attempts to target adaptive immune mediators will be critical for the development of novel therapeutic interventions.

TRPV4 channel opening mediates pressure-induced pancreatitis initiated by Piezo1 activation

Elevated pressure in the pancreatic gland is the central cause of pancreatitis following abdominal trauma, surgery, endoscopic retrograde cholangiopancreatography, and gallstones. In the pancreas, excessive intracellular calcium causes mitochondrial dysfunction, premature zymogen activation, and necrosis, ultimately leading to pancreatitis. Although stimulation of the mechanically activated, calcium-permeable ion channel Piezo1 in the pancreatic acinar cell is the initial step in pressure-induced pancreatitis, activation of Piezo1 produces only transient elevation in intracellular calcium that is insufficient to cause pancreatitis. Therefore, how pressure produces a prolonged calcium elevation necessary to induce pancreatitis is unknown. We demonstrate that Piezo1 activation in pancreatic acinar cells caused a prolonged elevation in intracellular calcium levels, mitochondrial depolarization, intracellular trypsin activation, and cell death. Notably, these effects were dependent on the degree and duration of force applied to the cell. Low or transient force was insufficient to activate these pathological changes, whereas higher and prolonged application of force triggered sustained elevation in intracellular calcium, leading to enzyme activation and cell death. All of these pathological events were rescued in acinar cells treated with a Piezo1 antagonist and in acinar cells from mice with genetic deletion of Piezo1. We discovered that Piezo1 stimulation triggered transient receptor potential vanilloid subfamily 4 (TRPV4) channel opening, which was responsible for the sustained elevation in intracellular calcium that caused intracellular organelle dysfunction. Moreover, TRPV4 gene-KO mice were protected from Piezo1 agonist- and pressure-induced pancreatitis. These studies unveil a calcium signaling pathway in which a Piezo1-induced TRPV4 channel opening causes pancreatitis.

Moderate alcohol intake promotes pancreatic ductal adenocarcinoma development in mice expressing oncogenic Kras

Kras mutations are associated with pancreatic ductal adenocarcinoma (PDAC). Although tobacco smoking, pancreatitis, and obesity are known environmental risk factors for PDAC, the contribution of moderate alcohol intake to PDAC remains elusive. In the present study, we tested whether a combination of risk factors or moderate alcohol intake induces PDAC development in mice. Control Pdx1^Cre and Pdx1^Cre;LSL-Kras^G12D mutant mice were fed a Western alcohol diet containing high levels of cholesterol and saturated fat, 3.5% alcohol, and lipopolysaccharide for 5 mo. In addition, mice were treated with cerulein, for induction of pancreatitis, and nicotine every month. Treatment with all of these risk factors promoted development of advanced pancreatic neoplasia and PDAC in the Pdx1^Cre;LSL-Kras^G12D mice but not in the control Pdx1^Cre mice. Moderate alcohol intake or Western diet feeding also significantly promoted advanced neoplasia and PDAC development in Pdx1^Cre;LSL-Kras^G12D mice compared with mice fed a regular chow. Alcohol, but not Western diet, increased tumor development in the liver in the Pdx1^Cre;LSL-Kras^G12D mice, but its origin remained elusive due to leakiness of Pdx1^Cre in hepatocytes. RNA-seq analysis revealed that alcohol feeding increases expression of markers for tumors (Epcam, Krt19, Prom1, Wt1, and Wwtr1), stroma (Dcn, Fn1, and Tnc), and cytokines (Tgfb1 and Tnf) and decreases expression of Fgf21 and Il6 in the pancreatic tumor tissues. Immunostaining showed heterogeneous expression of nephronectin, S100 calcium-binding protein A6, and vascular cell adhesion molecule 1 in pancreatic tumors surrounded by podoplanin-positive stromal cells. Our data indicate that moderate alcohol drinking is a risk factor for development of PDAC.NEW & NOTEWORTHY Heavy alcohol intake has been suspected to be a risk factor of pancreatic ductal adenocarcinoma (PDAC) in humans. However, the contribution of moderate alcohol intake to PDAC development remains elusive. In the present study, we experimentally show that moderate alcohol feeding significantly induces advanced stages of pancreatic intraepithelial neoplasia development and invasive PDAC in Pdx1^Cre;LSL-Kras^G12D mutant mice. Our data indicate that moderate alcohol drinking is a risk factor for PDAC.

Critical Role of TFEB-Mediated Lysosomal Biogenesis in Alcohol-Induced Pancreatitis in Mice and Humans

BACKGROUND & AIMS

Alcohol abuse is the major cause of experimental and human pancreatitis but the molecular mechanisms remain largely unknown. We investigated the role of transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, in the pathogenesis of alcoholic pancreatitis.

METHODS

Using a chronic plus acute alcohol binge (referred to as Gao-binge) mouse model, we analyzed pancreas injury, autophagic flux, zymogen granule removal, TFEB nuclear translocation and lysosomal biogenesis in GFP-LC3 transgenic mice, acinar cell-specific Atg5 knockout (KO) and TFEB KO mice as well as their matched wild type mice.

RESULTS

We found that Gao-binge alcohol induced typical features of pancreatitis in mice with increased serum amylase and lipase activities, pancreatic edema, infiltration of inflammatory cells, accumulation of zymogen granules (ZGs) and expression of inflammatory cytokines. While Gao-binge alcohol increased the number of autophagosomes, it also concurrently inhibited TFEB nuclear translocation and TFEB-mediated lysosomal biogenesis resulting in insufficient autophagy. Acinar cell-specific Atg5 KO and acinar cell-specific TFEB KO mice developed severe inflammatory and fibrotic pancreatitis in both Gao-binge alcohol and control diet-fed mice. In contrast, TFEB overexpression inhibited alcohol-induced pancreatic edema, accumulation of zymogen granules and serum amylase and lipase activities. In line with our findings in mice, decreased LAMP1 and TFEB nuclear staining were also observed in human alcoholic pancreatitis tissues.

CONCLUSIONS

our results indicate that TFEB plays a critical role in maintaining pancreatic acinar cell homeostasis. Impairment of TFEB-mediated lysosomal biogenesis by alcohol may lead to insufficient autophagy and promote alcohol-induced pancreatitis.

Stellate Cells in Tissue Repair, Inflammation, and Cancer

Stellate cells are resident lipid-storing cells of the pancreas and liver that transdifferentiate to a myofibroblastic state in the context of tissue injury. Beyond having roles in tissue homeostasis, stellate cells are increasingly implicated in pathological fibrogenic and inflammatory programs that contribute to tissue fibrosis and that constitute a growth-permissive tumor microenvironment. Although the capacity of stellate cells for extracellular matrix production and remodeling has long been appreciated, recent research efforts have demonstrated diverse roles for stellate cells in regulation of epithelial cell fate, immune modulation, and tissue health. Our present understanding of stellate cell biology in health and disease is discussed here, as are emerging means to target these multifaceted cells for therapeutic benefit.

Ductal Mucus Obstruction and Reduced Fluid Secretion Are Early Defects in Chronic Pancreatitis

Objective: Defective mucus production in the pancreas may be an important factor in the initiation and progression of chronic pancreatitis (CP), therefore we aimed to (i) investigate the qualitative and quantitative changes of mucus both in human CP and in an experimental pancreatitis model and (ii) to correlate the mucus phenotype with epithelial ion transport function.

Design: Utilizing human tissue samples and a murine model of cerulein induced CP we measured pancreatic ductal mucus content by morphometric analysis and the relative expression of different mucins in health and disease. Pancreatic fluid secretion in CP model was measured in vivo by magnetic resonance cholangiopancreatography (MRCP) and in vitro on cultured pancreatic ducts. Time-changes of ductal secretory function were correlated to those of the mucin production.

Results: We demonstrate increased mucus content in the small pancreatic ducts in CP. Secretory mucins MUC6 and MUC5B were upregulated in human, Muc6 in mouse CP. In vivo and in vitro fluid secretion was decreased in cerulein-induced CP. Analysis of time-course changes showed that impaired ductal ion transport is paralleled by increased Muc6 expression.

Conclusion: Mucus accumulation in the small ducts is a combined effect of mucus hypersecretion and epithelial fluid secretion defect, which may lead to ductal obstruction. These results suggest that imbalance of mucus homeostasis may have an important role in the early-phase development of CP, which may have novel diagnostic and therapeutic implications.

Chronic Pancreatitis: Current Status and Challenges for Prevention and Treatment

This paper reviews the current status of our understanding of the epidemiology, diagnosis, and management of the continuum of pancreatic diseases from acute and recurrent acute pancreatitis to chronic pancreatitis and the diseases that are often linked with pancreatitis including diabetes mellitus and pancreatic cancer. In addition to reviewing the current state of the field, we identify gaps in knowledge that are necessary to address to improve patient outcomes in these conditions.

Do Animal Models of Acute Pancreatitis Reproduce Human Disease?

Acute pancreatitis is currently the most common cause of hospital admission among all nonmalignant gastrointestinal diseases. To understand the pathophysiology of the disease and as a potential step toward developing targeted therapies, attempts to induce the disease experimentally began more than 100 years ago. Recent decades have seen progress in developing new experimental pancreatitis models as well as elucidating many underlying cell biological and pathophysiological disease mechanisms. Some models have been developed to reflect specific causes of acute pancreatitis in human beings. However, the paucity of data relating to the molecular mechanisms of human disease, the likelihood that multiple genetic and environmental factors affect the risk of disease development and its severity, and the limited information regarding the natural history of disease in human beings make it difficult to evaluate the value of disease models. Here, we provide an overview of key models and discuss our views on their strengths for characterizing cell biological disease mechanisms or for identifying potential therapeutic targets. We also acknowledge their limitations.

Biology of pancreatic stellate cells-more than just pancreatic cancer

Pancreatic stellate cells, normally quiescent, are capable of remarkable transition into their activated myofibroblast-like phenotype. It is now commonly accepted that these cells play a pivotal role in the desmoplastic reaction present in severe pancreatic disorders. In recent years, enormous scientific effort has been devoted to understanding their roles in pancreatic cancer, which continues to remain one of the most deadly diseases. Therefore, it is not surprising that considerably less attention has been given to studying physiological functions of pancreatic stellate cells. Here, we review recent advances not only in the field of pancreatic stellate cell pathophysiology but also emphasise their roles in physiological processes.

Animal models of gastrointestinal and liver diseases. Animal models of acute and chronic pancreatitis

Animal models of pancreatitis are useful for elucidating the pathogenesis of pancreatitis and developing and testing novel interventions. In this review, we aim to summarize the most commonly used animal models, overview their pathophysiology, and discuss their strengths and limitations. We will also briefly describe common animal study procedures and refer readers to more detailed protocols in the literature. Although animal models include pigs, dogs, opossums, and other animals, we will mainly focus on rodent models because of their popularity. Autoimmune pancreatitis and genetically engineered animal models will be reviewed elsewhere.

Alcohol and cigarette smoke components activate human pancreatic stellate cells: implications for the progression of chronic pancreatitis

BACKGROUND

Chronic pancreatitis, a known complication of alcohol abuse, is characterized histopathologically by prominent fibrosis. Pancreatic stellate cells (PSCs) are responsible for producing this fibrous tissue in chronic pancreatitis and are activated by alcohol. Progression of alcoholic chronic pancreatitis (as assessed by calcification and fibrosis) is thought to be facilitated by concurrent smoking, but the mechanisms are unknown. This study aimed to (a) determine whether human PSCs (hPSCs) and rat PSCs express nicotinic acetylcholine receptors (nAChRs), which are known to bind 2 important components of cigarette smoke, namely nicotine and nicotine-derived nitrosamine ketone (NNK), and (b) examine the effects of cigarette smoke components in the presence and absence of alcohol on PSC activation in vitro.

METHODS

Western blotting was used to detect the presence of nAChRs in primary cultures of PSCs. Clinically relevant concentrations of cigarette smoke components (either cigarette smoke extract [CSE], NNK, or nicotine) ± ethanol (EtOH) were used to treat primary cultures of PSCs, and stellate cell activation was assessed by cell migration, proliferation, collagen production, and apoptosis.

RESULTS

We demonstrate, for the first time, that PSCs express nAChRs (isoforms α3, α7, β, ε) and that the expression of the α7 isoform in hPSCs is induced by CSE + EtOH. We also provide novel findings that PSCs are activated by CSE and NNK (both alone and in combination with EtOH) as evidenced by an increase in cell migration and/or proliferation. Further, we demonstrate that activation of PSCs by CSE + EtOH and NNK + EtOH may be mediated via nAChRs on the cells.

CONCLUSIONS

PSCs are activated by clinically relevant concentrations of cigarette smoke components (CSE and NNK), alone and in combination with EtOH. Thus, in alcoholics who smoke, progression of pancreatic fibrosis may be facilitated by the combined effects of alcohol and cigarette smoke components on hPSC behavior.

Complement Component 5 Mediates Development of Fibrosis, via Activation of Stellate Cells, in 2 Mouse Models of Chronic Pancreatitis

BACKGROUND & AIMS

Little is known about the pathogenic mechanisms of chronic pancreatitis. We investigated the roles of complement component 5 (C5) in pancreatic fibrogenesis in mice and patients.

METHODS

Chronic pancreatitis was induced by ligation of the midpancreatic duct, followed by a single supramaximal intraperitoneal injection of cerulein, in C57Bl6 (control) and C5-deficient mice. Some mice were given injections of 2 different antagonists of the receptor for C5a over 21 days. In a separate model, mice were given injections of cerulein for 10 weeks to induce chronic pancreatitis. Direct effects of C5 were studied in cultured primary cells. We performed genotype analysis for the single-nucleotide polymorphisms rs 17611 and rs 2300929 in C5 in patients with pancreatitis and healthy individuals (controls). Blood cells from 976 subjects were analyzed by transcriptional profiling.

RESULTS

During the initial phase of pancreatitis, levels of pancreatic damage were similar between C5-deficient and control mice. During later stages of pancreatitis, C5-deficient mice and mice given injections of C5a-receptor antagonists developed significantly less pancreatic fibrosis than control mice. Primary pancreatic stellate cells were activated in vitro by C5a. There were no differences in the rs 2300929 SNP between subjects with or without pancreatitis, but the minor allele rs17611 was associated with a significant increase in levels of C5 in whole blood.

CONCLUSIONS

In mice, loss of C5 or injection of a C5a-receptor antagonist significantly reduced the level of fibrosis of chronic pancreatitis, but this was not a consequence of milder disease in early stages of pancreatitis. C5 might be a therapeutic target for chronic pancreatitis.

Pancreatic adaptive responses in alcohol abuse: Role of the unfolded protein response

The majority of those who drink excessive amounts of alcohol do not develop pancreatic disease. One overarching hypothesis is that alcohol abuse requires additional risk factors, either environmental or genetic, for disease to occur. However, another reason be a result of alcohol-induced activation of adaptive systems that protect the pancreas from the toxic effects of alcohol. We show that mechanisms within the unfolded protein response (UPR) of the endoplasmic reticulum (ER) that can lead to protection of the pancreas from pancreatic diseases with alcohol abuse. The remarkable ability of the pancreas to adapt its machinery to alcohol abuse using UPR systems and continue functioning is the likely reason that pancreatitis from alcohol abuse does not occur in the majority of heavy drinkers. These findings indicate that methods to enhance the protective responses of the UPR can provide opportunities for prevention and treatment of pancreatic diseases.

Immune cells and immune-based therapy in pancreatitis

Alcohol and gallstones are the most common etiologic factors in acute pancreatitis (AP). Recurrent AP can lead to chronic pancreatitis (CP). Although the underlying pathophysiology of the disease is complex, immune cells are critical in the pathogenesis of pancreatitis and determining disease severity. In this review, we discuss the role of innate and adaptive immune cells in both AP and CP, potential immune-based therapeutic targets, and animal models used to understand our knowledge of the disease. The relative difficulty of obtaining human pancreatic tissue during pancreatitis makes animal models necessary. Animal models of pancreatitis have been generated to understand disease pathogenesis, test therapeutic interventions, and investigate immune responses. Although current animal models do not recapitulate all aspects of human disease, until better models can be developed available models are useful in addressing key research questions. Differences between experimental and clinical pancreatitis need consideration, and when therapies are tested, models with established disease ought to be included.

Stars and stripes in pancreatic cancer: role of stellate cells and stroma in cancer progression

Pancreatic cancer is a devastating disease with an unacceptably high mortality to incidence ratio. Traditional therapeutic approaches such as surgery in combination with chemo- or radiotherapy have had limited efficacy in improving the outcome of this disease. Up until just under a decade ago, the prominent desmoplastic reaction which is a characteristic of the majority of pancreatic ductal adenocarcinomas (PDAC) had been largely ignored. However, since the identification of the pancreatic stellate cell (PSC) as the key cell responsible for the production of the collagenous stroma in PDAC, increasing attention has been paid to the role of the stromal reaction in pancreatic cancer pathobiology. There is now compelling evidence that PSCs interact not only with cancer cells themselves, but with several other cell types in the stroma (endothelial cells, immune cells, and possibly neuronal cells) to promote cancer progression. This review summarizes current knowledge in the field about the influence of PSCs and the stromal microenvironment on cancer behavior and discusses novel therapeutic approaches which reflect an increasing awareness amongst clinicians and researchers that targeting cancer cells alone is no longer sufficient to improve patient outcome and that combinatorial treatments targeting the stroma as well as the cancer cells will be required to change the clinical course of this disease.

Risk factors for pancreatic cancer: underlying mechanisms and potential targets

PURPOSE OF THE REVIEW

Pancreatic cancer is extremely aggressive, forming highly chemo-resistant tumors, and has one of the worst prognoses. The evolution of this cancer is multi-factorial. Repeated acute pancreatic injury and inflammation are important contributing factors in the development of pancreatic cancer. This article attempts to understand the common pathways linking pancreatitis to pancreatic cancer.

RECENT FINDINGS

Intracellular activation of both pancreatic enzymes and the transcription factor NF-κB are important mechanisms that induce acute pancreatitis (AP). Recurrent pancreatic injury due to genetic susceptibility, environmental factors such as smoking, alcohol intake, and conditions such as obesity lead to increases in oxidative stress, impaired autophagy and constitutive activation of inflammatory pathways. These processes can stimulate pancreatic stellate cells, thereby increasing fibrosis and encouraging chronic disease development. Activation of oncogenic Kras mutations through inflammation, coupled with altered levels of tumor suppressor proteins (p53 and p16) can ultimately lead to development of pancreatic cancer.

SUMMARY

Although our understanding of pancreatitis and pancreatic cancer has tremendously increased over many years, much remains to be elucidated in terms of common pathways linking these conditions.

Role of pancreatic fat in the outcomes of pancreatitis

The role of obesity in relation to various disease processes is being increasingly studied, with reports over the last several years increasingly mentioning its association with worse outcomes in acute disease. Obesity has also gained recognition as a risk factor for severe acute pancreatitis (SAP).The mortality in SAP may be as high as 30% and is usually attributable to multi system organ failure (MSOF) earlier in the disease, and complications of necrotizing pancreatitis later [9-11]. To date there is no specific treatment for acute pancreatitis (AP) and the management is largely expectant and supportive. Obesity in general has also been associated with poor outcomes in sepsis and other pathological states including trauma and burns. With the role of unsaturated fatty acids (UFA) as propagators in SAP having recently come to light and with the recognition of acute lipotoxicity, there is now an opportunity to explore different strategies to reduce the mortality and morbidity in SAP and potentially other disease states associated with such a pathophysiology. In this review we will discuss the role of fat and implications of the consequent acute lipotoxicity on the outcomes of acute pancreatitis in lean and obese states and during acute on chronic pancreatitis.

Alcohol exacerbates LPS-induced fibrosis in subclinical acute pancreatitis

The role of pancreatic acinar cells in initiating fibrogenic responses during the early stages of alcoholic acute pancreatitis has not been evaluated. We investigated the ability of injured acinar cells to generate pancreatic fibrosis in acute pancreatitis. Rats were fed either an ethanol-containing or control diet over 14 weeks and euthanized 3 or 24 hours after a single lipopolysaccharide injection. Profibrotic transforming growth factor-β of acinar cells and pancreatic fibrosis were assessed by immunofluorescence, histological characteristics, and electron microscopy. Human pancreatic tissues were also evaluated. Periacinar cell fibrosis and collagen were exacerbated 24 hours after endotoxemia in alcohol-fed rats. Alcohol exposure exacerbated acinar cell-specific production of transforming growth factor β in response to lipopolysaccharide in vivo and in acinar cell-like AR42J cells in vitro. Although a morphological examination showed no visible signs of necrosis, early pancreatic fibrosis can be initiated by little or no pancreatic necrosis. Transforming growth factor β was also significantly increased in human acinar cells from patients with acute/recurrent pancreatitis compared with chronic pancreatitis tissue. Alcohol exacerbates lipopolysaccharide-induced pancreatic fibrosis during the early onset of mild, subclinical, acute pancreatitis. We suggest that multiple, subclinical, acute pancreatitis episodes can accumulate in fibrosis during the development of chronic pancreatitis, even if there is no history of acute pancreatitis.

New insights into the pathogenesis of pancreatitis

PURPOSE OF REVIEW

In this article, we review important advances in our understanding of the mechanisms of pancreatitis.

RECENT FINDINGS

The relative contributions of intrapancreatic trypsinogen activation and nuclear factor kappa B (NFκB) activation, the two major early independent cellular events in pancreatitis, have been investigated using novel genetic models. Trypsinogen activation has traditionally held the spotlight for many decades as the central pathogenic event of pancreatitis. However, recent experimental evidence points to the role of trypsin activation in early acinar cell damage but not in the inflammatory response of acute pancreatitis, which was shown to be induced by NFκB activation. Further, chronic pancreatitis developed independently of trypsinogen activation in the caerulein model. Sustained NFκB activation, but not persistent intra-acinar expression of active trypsin, was shown to result in chronic pancreatitis. Calcineurin-NFAT (nuclear factor of activated T-cells) signaling was shown to mediate downstream effects of pathologic rise in intracellular calcium. Interleukin-6 was identified as a key cytokine mediating pancreatitis-associated lung injury.

SUMMARY

Recent advances challenge the long-believed trypsin-centered understanding of pancreatitis. It is becoming increasingly clear that activation of intense inflammatory signaling mechanisms in acinar cells is crucial to the pathogenesis of pancreatitis, which may explain the strong systemic inflammatory response in pancreatitis.

Models of acute and chronic pancreatitis

Animal models of acute and chronic pancreatitis have been created to examine mechanisms of pathogenesis, test therapeutic interventions, and study the influence of inflammation on the development of pancreatic cancer. In vitro models can be used to study early stage, short-term processes that involve acinar cell responses. Rodent models reproducibly develop mild or severe disease. One of the most commonly used pancreatitis models is created by administration of supraphysiologic concentrations of caerulein, an ortholog of cholecystokinin. Induction of chronic pancreatitis with factors thought to have a role in human disease, such as combinations of lipopolysaccharide and chronic ethanol feeding, might be relevant to human disease. Models of autoimmune chronic pancreatitis have also been developed. Most models, particularly of chronic pancreatitis, require further characterization to determine which features of human disease they include.

Cerulein-induced chronic pancreatitis does not require intra-acinar activation of trypsinogen in mice

BACKGROUND & AIMS

Premature activation of trypsinogen activation can cause pancreatic injury and has been associated with chronic pancreatitis (CP). Mice that lack intra-acinar activation of trypsinogen, such as trypsinogen-7-null (T(-/-)) and cathepsin B-null (CB(-/-)) mice, have been used to study trypsin-independent processes of CP development. We compared histologic features and inflammatory responses of pancreatic tissues from these mice with those from wild-type mice after the development of CP.

METHODS

CP was induced in wild-type, T(-/-), and CB(-/-) mice by twice-weekly induction of acute pancreatitis for 10 weeks; acute pancreatitis was induced by hourly intraperitoneal injections of cerulein (50 μg/kg × 6). Pancreatic samples were collected and evaluated by histologic and immunohistochemical analyses. Normal human pancreas samples, obtained from the islet transplant program at the University of Minnesota, were used as controls and CP samples were obtained from surgical resections.

RESULTS

Compared with pancreatic tissues from wild-type mice, those from T(-/-) and CB(-/-) mice had similar levels of atrophy, histomorphologic features of CP, and chronic inflammation. All samples had comparable intra-acinar activation of nuclear factor (NF)-κB, a transcription factor that regulates the inflammatory response, immediately after injection of cerulein. Pancreatic tissue samples from patients with CP had increased activation of NF-κB (based on nuclear translocation of p65 in acinar cells) compared with controls.

CONCLUSIONS

Induction of CP in mice by cerulein injection does not require intra-acinar activation of trypsinogen. Pancreatic acinar cells of patients with CP have increased levels of NF-κB activation compared with controls; regulation of the inflammatory response by this transcription factor might be involved in the pathogenesis of CP.

Prolonged high fat/alcohol exposure increases TRPV4 and its functional responses in pancreatic stellate cells

The present study investigated transient receptor potential vanilloid type 4 (TRPV4) ion channels in pancreatic stellate cells (PSCs) isolated from rats with high-fat and alcohol diet (HFA)-induced chronic pancreatitis. TRPV4 is a calcium-permeable nonselective ion channel responsive to osmotic changes, alcohol metabolites arachidonic acid, anandamide, their derivatives, and injury-related lipid mediators. Male Lewis rats were fed HFA for 6-8 wk before isolation and primary culture of PSCs. Control PSCs were harvested from rats fed standard chow. Immunoreactivity for cytoskeletal protein activation product α-smooth muscle actin (α-SMA) and platelet-derived growth factor receptor-β subunit (PDGFR-β) characterized the cells as PSCs. TRPV4 expression increased in PSCs of HFA-fed rats and control cultures after alcohol treatment (50 mM). Cell responses to activation of inducible TRPV4 were assessed with live cell calcium imaging. Threefold increased and sustained intracellular calcium mobilization responses occurred in 70% of pancreatic stellate cells from HFA-fed rats in response to TRPV4 activators arachidonic acid, lipid second messenger, phorbol ester 4 α-phorbol 12,13-didecanoate (4αPDD), and 50% hypoosmotic media compared with relatively unresponsive PSCs from control rats. Activation responses were attenuated by nonselective TRPV channel blocker ruthenium red. Tumor necrosis factor-α (TNF-α, 1 ng/ml, 16 h) increased responses to 4αPDD in control PSCs. These findings implicate TRPV4-mediated calcium responses inducible after HFA exposure and inflammation in reactive responses of activated PSCs that impair pancreatic function, such as responsiveness to cytokines and the deposition of collagen fibrosis that precipitates ductal blockage and pain.

Controversial role of toll-like receptors in acute pancreatitis

Acute pancreatitis (AP) is a common clinical condition with an incidence of about 300 or more patients per million annually. About 10%-15% of patients will develop severe acute pancreatitis (SAP) and of those, 10%-30% may die due to SAP-associated complications. Despite the improvements done in the diagnosis and management of AP, the mortality rate has not significantly declined during the last decades. Toll-like receptors (TLRs) are pattern-recognition receptors that seem to play a major role in the development of numerous diseases, which make these molecules attractive as potential therapeutic targets. TLRs are involved in the development of the systemic inflammatory response syndrome, a potentially lethal complication in SAP. In the present review, we explore the current knowledge about the role of different TLRs that have been described associated with AP. The main candidate for targeting seems to be TLR4, which recognizes numerous damage-associated molecular patterns related to AP. TLR2 has also been linked with AP, but there are only limited studies that exclusively studied its role in AP. There is also data suggesting that TLR9 may play a role in AP.

ERK pathway and sheddases play an essential role in ethanol-induced CX3CL1 release in pancreatic stellate cells

The clinical course of chronic pancreatitis (CP) worsens with drinking, and pancreatic stellate cells (PSCs) have an important role in the pathogenesis of alcoholic CP. Chemokines recruit inflammatory cells, resulting in chronic pancreatic inflammation. Although serum levels of fractalkine (CX3CL1) are significantly elevated in patients with alcoholic CP, the mechanism of this elevation remains unclear. This study aims to determine the effects of cytokines, pathogen-associated molecular patterns (PAMPs), and ethanol and its metabolites on CX3CL1 secretion by PSCs. Male Wistar/Bonn Kobori (WBN/Kob) rats aged 15 to 20 weeks were used as rodent models of CP in vivo. PSCs were isolated from 6-week-old male Wistar rats. The effects of cytokines, PAMPs, and ethanol and its metabolites on chemokine production and activation of signaling pathways in PSCs in vitro were examined by real-time reverse transcription-polymerase chain reaction (RT-PCR), western blotting, and enzyme-linked immunosorbent assay. Expression of CX3CL1 and matrix metalloprotease (MMP)-2 was increased in the pancreas of WBN/Kob rats. The rat PSCs expressed CX3CL1, MMP-2, and a disintegrin and metalloprotease domain (ADAM) 17. Cytokines and PAMPs induced CX3CL1 release and activated extracellular signal-regulated kinase (ERK), MMP-9, and ADAM17. CX3CL1 release was suppressed by specific inhibitors of ERK, MMP, and ADAM, and ERK was associated with CX3CL1 transcription. Ethanol and phorbol myristate acetate synergistically increased CX3CL1 release. Real-time PCR and western blotting confirmed the synergistic activation of ERK and ADAM17. Ethanol synergistically increased CX3CL1 release via ERK and ADAM17 activation in PSCs. In conclusion, we demonstrated for the first time that ethanol synergistically increased CX3CL1 release from PSCs at least in part through activation of ERK mitogen-activated protein kinase and ADAM17. This might be one of the mechanisms of serum CX3CL1 elevation and disease progression in patients with alcoholic CP.

Chronic pancreatitis

PURPOSE OF REVIEW

We review important new clinical observations in chronic pancreatitis reported in 2011.

RECENT FINDINGS

Smoking increases the risk of nongallstone acute pancreatitis and the progression of acute pancreatitis to chronic pancreatitis. Binge drinking during Oktoberfest did not associate with increased hospital admissions for acute pancreatitis. The unfolded protein response is an adaptive mechanism to maintain pancreatic health in response to noxious stimuli such as alcohol. Onset of diabetes mellitus in chronic pancreatitis is likely due to progressive disease rather than individual variables. Insufficient pancreatic enzyme dosing is common for treatment of pancreatic steatorrhea; 90 000 United States Pharmacopeia units of lipase should be given with meals. Surgical drainage provides sustained, superior pain relief compared with endoscopic treatment in patients advanced chronic pancreatitis with a dilated main duct ± pancreatic stones. The central acting gabapentoid pregabalin affords a modest 12% pain reduction in patients with chronic pancreatitis but approximately 30% of patients have significant side effects.

SUMMARY

Patients with nongallstone-related acute pancreatitis or chronic pancreatitis of any cause should cease smoking. Results of this year's investigations further elucidated the pancreatic pathobiology due to alcohol, onset of diabetes mellitus in chronic pancreatitis, and the mechanisms and treatment of neuropathic pain in chronic pancreatitis.

Pancreatic stellate cells: a starring role in normal and diseased pancreas

While the morphology and function of cells of the exocrine and endocrine pancreas have been studied over several centuries, one important cell type in the gland, the pancreatic stellate cell (PSC), had remained undiscovered until as recently as 20 years ago. Even after its first description in 1982, it was to be another 16 years before its biology could begin to be studied, because it was only in 1998 that methods were developed to isolate and culture PSCs from rodent and human pancreas. PSCs are now known to play a critical role in pancreatic fibrosis, a consistent histological feature of two major diseases of the pancreas—chronic pancreatitis and pancreatic cancer. In health, PSCs maintain normal tissue architecture via regulation of the synthesis and degradation of extracellular matrix (ECM) proteins. Recent studies have also implied other functions for PSCs as progenitor cells, immune cells or intermediaries in exocrine pancreatic secretion in humans. During pancreatic injury, PSCs transform from their quiescent phase into an activated, myofibroblast-like phenotype that secretes excessive amounts of ECM proteins leading to the fibrosis of chronic pancreatitis and pancreatic cancer. An ever increasing number of factors that stimulate and/or inhibit PSC activation via paracrine and autocrine pathways are being identified and characterized. It is also now established that PSCs interact closely with pancreatic cancer cells to facilitate cancer progression. Based on these findings, several therapeutic strategies have been examined in experimental models of chronic pancreatitis as well as pancreatic cancer, in a bid to inhibit/retard PSC activation and thereby alleviate chronic pancreatitis or reduce tumor growth in pancreatic cancer. The challenge that remains is to translate these pre-clinical developments into clinically applicable treatments for patients with chronic pancreatitis and pancreatic cancer.

Long-lasting effect of infant rats endotoxemia on heat shock protein 60 in the pancreatic acinar cells: involvement of toll-like receptor 4

Introduction. Lipopolysaccharide endotoxin (LPS) is responsible for septic shock and multiorgan failure, but pretreatment of rats with low doses of LPS reduced pancreatic acute damage. Aim. We investigated the effects of the endotoxemia induced in the early period of life on Toll-like receptor 4 (TLR4), heat shock protein 60 (HSP60) and proapoptotic Bax, caspase-9 and -3 or antiapoptotic Bcl-2 protein expression in the pancreatic acinar cells of adult animals. Material and Methods. Newborn rats (25 g) were injected with endotoxin (Escherichia coli) for 5 consecutive days. Two months later, pancreatic acinar cells were isolated from all groups of animals and subjected to caerulein stimulation (10⁻⁸ M). Protein expression was assessed employing Western blot. For detection of apoptosis we have employed DNA fragmentation ladder assay. Results. Preconditioning of newborn rats with LPS increased TLR4, Caspase-9 and -3 levels, but failed to affect basal expression of HSP60, Bax, and Bcl-2. Subsequent caerulein stimulation increased TLR4, Bcl-2, and caspases, but diminished HSP60 and Bax proteins in pancreatic acinar cells. Endotoxemia dose-dependently increased TLR4, Bax, HSP60, and both caspases protein signals in the pancreatic acini, further inhibiting antiapoptotic Bcl-2. Conclusions. Endotoxemia promoted the induction of HSP60 via TLR4 in the infant rats and participated in the LPS-dependent pancreatic tissue protection against acute damage.

Alcoholic acute pancreatitis: pathogenesis and clinical characteristics

Animal and clinical studies have shown that alcohol and its metabolic products, endotoxin, viral infection, drinking pattern, smoking, obesity, genetic variability, and gene polymorphisms were very important in the pathogenesis of alcoholic acute pancreatitis (AAP). The morbidity of AAP has been increased in the past decade, and male gender is strongly associated with increased risk of AAP. The mortality of AAP is high, while the quality of life of survivors of severe AAP is low. In this paper, we review the pathogenesis and clinical characteristics of AAP.