Bacterial endotoxin: a trigger factor for alcoholic pancreatitis? Evidence from a novel, physiologically relevant animal model

Pdgfrα+ stromal cells, a key regulator for tissue homeostasis and dysfunction in distinct organs

Pdgfrα+ stromal cells are a group of cells specifically expressing Pdgfrα, which may be mentioned with distinct names in different tissues. Importantly, the findings from numerous studies suggest that these cells share exactly similar biomarkers and properties, show complex functions in regulating the microenvironment, and are critical to tissue regeneration, repair, and degeneration. Comparing the similarities and differences between distinct tissue-resident Pdgfrα+ stromal cells is helpful for us to more comprehensively and deeply understand the behaviors of these cells and to explore some common regulating mechanisms and therapeutical targets. In this review, we summarize previous and current findings on Pdgfrα+ stromal cells in various tissues and discuss the crosstalk between Pdgfrα+ stromal cells and microenvironment.

New Progress in the Study of Pathogenesis of Alcoholic Pancreatitis

BACKGROUND

Alcoholic pancreatitis is a progressive condition characterized by susceptibility to recurrence, progression to chronic pancreatitis, complications, and high morbidity.

SUMMARY

The main causes include long-term alcoholism, excessive drinking, the toxic effects of alcohol metabolites, interactions with biliary diseases, and genetic factors. Alcohol is the second leading cause of acute pancreatitis (AP) in the USA, accounting for one-third of all AP cases. A follow-up study on readmission revealed that the readmission rate of alcoholic acute pancreatitis (AAP) patients within 11 months was 43.1%, of which men dominated the admissions and readmissions of AAP. Among this population, 82.3% have alcohol use disorder, over half have tobacco use disorders, 6.7% have tobacco use disorder, 4.5% have opioid use disorder, and 18.5% of patients exhibit signs of potential alcoholic chronic pancreatitis. Numerous animal and clinical studies suggest that alcohol alone does not cause pancreatitis; rather, additional factors such as smoking, endotoxin lipopolysaccharide (LPS), genetic mutations, or other genetic predispositions - are necessary for the disease's progression.

KEY MESSAGES

Given the high rates of admission and readmission for alcoholic pancreatitis, it is essential to further investigate its pathogenesis and pathological processes to develop more effective treatment strategies. Therefore, this paper summarizes the current understanding of the pathogenesis and treatment status of alcoholic pancreatitis, drawing on recently published literature and data to provide insights and references for future research and treatment efforts.

Renalase peptides reduce pancreatitis severity in mice

Acute pancreatitis, an acute inflammatory injury of the pancreas, lacks a specific treatment. The circulatory protein renalase is produced by the kidney and other tissues and has potent anti-inflammatory and prosurvival properties. Recombinant renalase can reduce the severity of mild cerulein pancreatitis; the activity is contained in a conserved 20 aa renalase site (RP220). Here, we investigated the therapeutic effects of renalase on pancreatitis using two clinically relevant models of acute pancreatitis. The ability of peptides containing the RP220 site to reduce injury in a 1-day post-endoscopic retrograde cholangiopancreatography (ERCP) and a 2-day severe cerulein induced in mice was examined. The initial dose of renalase peptides was given either prophylactically (before) or therapeutically (after) the initiation of the disease. Samples were collected to determine early pancreatitis responses (tissue edema, plasma amylase, active zymogens) and later histologic tissue injury and inflammatory changes. In both preclinical models, renalase peptides significantly reduced histologic damage associated with pancreatitis, especially inflammation, necrosis, and overall injury. Quantifying inflammation using specific immunohistochemical markers demonstrated that renalase peptides significantly reduced overall bone marrow-derived inflammation and neutrophils and macrophage populations in both models. In the severe cerulein model, administering a renalase peptide with or without pretreatment significantly reduced injury. Pancreatitis and renalase peptide effects appeared to be the same in female and male mice. These studies suggest renalase peptides that retain the anti-inflammatory and prosurvival properties of recombinant renalase can reduce the severity of acute pancreatitis and might be attractive candidates for therapeutic development.NEW & NOTEWORTHY Renalase is a secretory protein. The prosurvival and anti-inflammatory effects of the whole molecule are contained in a 20 aa renalase site (RP220). Systemic treatment with peptides containing this renalase site reduced the severity of post-endoscopic retrograde cholangiopancreatography (ERCP) and severe cerulein pancreatitis in mouse models.

The Role of the Gut Microbiome in the Development of Acute Pancreatitis

With the explosion research on the gut microbiome in the recent years, much insight has been accumulated in comprehending the crosstalk between the gut microbiota community and host health. Acute pancreatitis (AP) is one of the gastrointestinal diseases associated with significant morbidity and subsequent mortality. Studies have elucidated that gut microbiota are engaged in the pathological process of AP. Herein, we summarize the major roles of the gut microbiome in the development of AP. We then portray the association between dysbiosis of the gut microbiota and the severity of AP. Finally, we illustrate the promises and challenges that arise when seeking to incorporate the microbiome in acute pancreatitis treatment.

Understanding bacterial infiltration of the pancreas through a deformable pancreatic duct

Tiny amount of bacteria are found in the pancreas in pancreatitis and cancer, which seemed involved in inflammation and carcinogenesis. However, bacterial infiltration from the duodenum is inhibited by the physical defense mechanisms such as bile flow and the sphincter of Oddi. To understand how the bacteria possibly infiltrate the pancreas through a deformable pancreatic duct, influenced by the periodic contractions of the sphincter of Oddi, a mathematical model of bacterial infiltration is developed that considered large deformation, fluid flow, and bacterial transport in a deformable pancreatic duct. In addition, the sphincter's contraction wave is modeled by including its propagation from the pancreas toward the duodenum. Simulated structure of the deformed duct with the relaxed sphincter and simulated bile distribution agreed reasonably well with the literature, validating the model. Bacterial infiltration from the duodenum in a deformable pancreatic duct, following the sphincter's contraction, is counteracted by a gradual peristalsis-like deformation of the pancreatic duct, due to an antegrade contraction wave propagation from the pancreas to the duodenum, Parametric sensitivity analysis demonstrated that bacterial infiltration is increased with lower bile and pancreatic juice flow rate, greater contraction amplitude and frequency, thinner wall thickness, and retrograde contraction wave propagation. Since contraction waves following retrograde propagation are increased in patients with common bile duct stones and pancreatitis, they may possibly be factors for continuum inflammation of pancreas. (224 words).

Modulatory action of Moringa oleifera Lam. on L-arginine induced acute pancreatitis

OBJECTIVES

Acute pancreatitis (AP) is an inflammatory disease of the pancreas with high morbidity and mortality. This study investigates the effect of Moring oleifera (MO) on L-arginine-induced AP in Wistar rats.

METHODS

Male Wistar rats were randomly divided into seven groups. Control, AP, Magnesium groups, all fed with standard rat diet, MO leaf groups (5% MLF and 15% MLF), and MO seed groups (5% MSD and 15% MSD) were fed with five or 15% MO leaf or seed supplemented diet for four weeks prior to induction of AP. AP was induced by administration of double doses of L-arginine (320 mg/100 g i.p.) at 1 h interval. All animals were sacrificed 72 h thereafter.

RESULTS

Weekly mean feed consumption and body weight were significantly higher in MO groups compared to the control. Amylase level, MDA, MPO, and NO were significantly higher in the AP group than in the control but decreased in Mg and MO groups. While CAT, SOD, GSH, and SH-group were significantly depleted in AP groups, which was attenuated in MO groups. Rats in AP groups showed severe inflammation, necrosis, and edema. These effects were significantly improved in MO groups resulting in lower histological scores compared to the AP group.

CONCLUSIONS

Pretreatment with MO could attenuate AP via its antioxidant and anti-inflammatory action.

Risk and Status of Gastrointestinal Cancer According to the International Standard Industrial Classification in Korean Workers

Simple Summary

The risk of developing cancers varies depending on occupation, which is a well-known fact. It is crucial to investigate the risk of developing gastrointestinal (GI) cancer in the entire industry. In this study, we calculated the standardized incidence ratios (SIRs) of GI cancer by all industrial sectors as classified in the Korean Standard Industrial Classification (KSIC). There were noticeable differences among industries in the risk of GI cancer. The SIR of all GI cancer was highest among miners and quarriers, and second highest among transportation workers. These results suggest that further research is required to identify the risk factors present in each industry that contribute to the development of GI cancers. We believe this study can help to create tailored cancer prevention strategies for different industrial sectors.

Abstract

To compare the risk of developing gastrointestinal (GI) cancer according to industrial groups, we performed a retrospective cohort study using the database of the Korea National Health Insurance Service (NHIS). We calculated the age-standardized incidence ratios (SIRs) and 95% confidence intervals (95% CIs) for the types of GI cancers according to the Korean Standard Industrial Classification (KSIC) compared with the whole employee population. The highest SIR for all GI cancer was found in the “Mining and quarrying” section (SIR, 1.30; 95% CI, 1.14–1.47), followed by the “Transportation and storage” section (SIR, 1.27; 95% CI, 1.24–1.30). Miners and quarriers had the highest risk of developing gastric cancer (SIR, 1.29; 95% CI, 1.06–1.55) and cancer of the liver and intrahepatic bile ducts (SIR, 1.48; 95% CI, 1.17–1.86). Transportation workers had the highest SIR of cancer of the lip, oral cavity, and pharynx (SIR, 1.27; 95% CI, 1.13–1.43) and cancers of the rectum, anus, and anal canal (SIR, 1.27; 95% CI, 1.19–1.35). There were distinct GI cancers with an elevated risk in each industry group. Our findings imply that distinct cancer prevention programs should be developed for each industrial sector.

Repeated Stimulation of Toll-Like Receptor 2 and Dectin-1 Induces Chronic Pancreatitis in Mice Through the Participation of Acquired Immunity

BACKGROUND

Stimulation of Toll-like receptor 3 (TLR3) induces autoimmune-mediated pancreatitis in susceptible mice, whereas stimulation of TLR4 causes nonautoimmune-mediated pancreatitis. However, the effects of TLR2 stimulation on the pancreas are unknown.

AIMS

We investigated the role of TLR2 stimulation on pancreatic damage by repeatedly stimulating mice with TLR2 ligands.

METHODS

Wild-type (WT) and interleukin 10-deficient (IL-10-knockout (KO)) mice were administered zymosan and lipoteichoic acid (LTA) intraperitoneally at various doses twice weekly for 4 weeks. Syngeneic T-cell-deficient mice, B-cell-deficient mice, recombination activating gene 2-deficient (RAG2-KO) mice and RAG2-KO mice that had been reconstituted with CD4⁺ or CD8⁺ T cells isolated from WT mice were treated with zymosan similarly. Mice were killed, the severity of pancreatitis was graded histologically, and serum cytokine levels were measured.

RESULTS

Repeated administration of zymosan induced pancreatitis dose dependently in both WT and IL-10-KO mice. Administration of LTA induced pancreatitis only in IL-10-KO mice. Adoptive transfer of splenocytes obtained from IL-10-KO mice with pancreatitis did not cause pancreatitis in recipient RAG2-KO mice. Pancreatitis was scarcely observed in RAG2-KO mice and was attenuated in T-cell-deficient and B-cell-deficient mice compared with WT mice. A single administration of zymosan significantly increased the serum level of monocyte chemoattractant protein 1 (MCP-1) in WT mice.

CONCLUSIONS

Repeated stimulation of TLR2 and dectin-1 induced nonautoimmune-mediated pancreatitis in mice. Participation of acquired immunity seems to play an important role in the pathogenesis of pancreatitis in association with the increase in serum MCP-1 level.

MIF confers survival advantage to pancreatic CAFs by suppressing interferon pathway-induced p53-dependent apoptosis

The presence of activated pancreatic stellate cells (PSCs) in the pancreatic ductal adenocarcinoma (PDAC) microenvironment plays a significant role in cancer progression. Macrophage migration inhibitory factor (MIF) is overexpressed in PDAC tissues and expressed by both cancer and stromal cells. The pathophysiological role of MIF in PDAC-associated fibroblasts or PSCs is yet to be elucidated. Here we report that the PSCs of mouse or cancer-associated fibroblast cells (CAFs) of human expresses MIF and its receptors, whose expression gets upregulated upon LPS or TNF-α stimulation. In vitro functional experiments showed that MIF significantly conferred a survival advantage to CAFs/PSCs upon growth factor deprivation. Genetic or pharmacological inhibition of MIF also corroborated these findings. Further, co-injection of mouse pancreatic cancer cells with PSCs isolated from Mif-/- or Mif+/+ mice confirmed the pro-survival effect of MIF in PSCs and also demonstrated the pro-tumorigenic role of MIF expressed by CAFs in vivo. Differential gene expression analysis and in vitro mechanistic studies indicated that MIF expressed by activated CAFs/PSCs confers a survival advantage to these cells by suppression of interferon pathway induced p53 dependent apoptosis.

TRPV6 channel mediates alcohol-induced gut barrier dysfunction and systemic response

Intestinal epithelial tight junction disruption is a primary contributing factor in alcohol-associated endotoxemia, systemic inflammation, and multiple organ damage. Ethanol and acetaldehyde disrupt tight junctions by elevating intracellular Ca²⁺. Here we identify TRPV6, a Ca²⁺-permeable channel, as responsible for alcohol-induced elevation of intracellular Ca²⁺, intestinal barrier dysfunction, and systemic inflammation. Ethanol and acetaldehyde elicit TRPV6 ionic currents in Caco-2 cells. Studies in Caco-2 cell monolayers and mouse intestinal organoids show that TRPV6 deficiency or inhibition attenuates ethanol- and acetaldehyde-induced Ca²⁺ influx, tight junction disruption, and barrier dysfunction. Moreover, Trpv6^−/− mice are resistant to alcohol-induced intestinal barrier dysfunction. Photoaffinity labeling of 3-azibutanol identifies a histidine as a potential alcohol-binding site in TRPV6. The substitution of this histidine, and a nearby arginine, reduces ethanol-activated currents. Our findings reveal that TRPV6 is required for alcohol-induced gut barrier dysfunction and inflammation. Molecules that decrease TRPV6 function have the potential to attenuate alcohol-associated tissue injury.

Meena et al. show that the mechanism of alcohol-induced gut permeability, endotoxemia, and systemic inflammation requires the TRPV6 channel. They show that ethanol activates TRPV6, induces calcium influx, and disrupts intestinal epithelial tight junctions. Furthermore, specific histidine and arginine residues at the N terminus fine-tune the alcohol-induced activation of TRPV6.

Sequestration of Intestinal Acidic Toxins by Cationic Resin Attenuates Pancreatic Cancer Progression through Promoting Autophagic Flux for YAP Degradation

Simple Summary

Annually, more than 450,000 people are diagnosed with pancreatic cancer worldwide with over 430,000 mortalities. Pancreatic ductal carcinoma (PDAC) accounts for around 80% of pancreatic cancer cases with an extremely high mortality rate. Emerging research has demonstrated that gut dysbiosis is closely associated with pancreatic cancer, while the underlying mechanisms remain elusive. In this study, we found that elevated levels of endotoxin (LPS) and bile acids were associated with malignant progression in Kras-driven pancreatic cancer mice. Importantly, oral administration of cationic resins to sequestrate intestinal endotoxins and bile acids efficiently attenuated tumor progression. Thus, sequestration of intestinal acidic toxins by oral administration of cationic resins may have potential as an intervention strategy for pancreatic malignancy.

Abstract

Pancreatic cancer is driven by risk factors such as diabetes and chronic pancreatic injury, which are further associated with gut dysbiosis. Intestinal toxins such as bile acids and bacterial endotoxin (LPS), in excess and persistence, can provoke chronic inflammation and tumorigenesis. Of interest is that many intestinal toxins are negatively charged acidic components in essence, which prompted us to test whether oral administration of cationic resin can deplete intestinal toxins and ameliorate pancreatic cancer. Here, we found that increased plasma levels of endotoxin and bile acids in Pdx1-Cre: LSL-Kras^G12D/+ mice were associated with the transformation of the pancreatic ductal carcinoma (PDAC) state. Common bile-duct-ligation or LPS injection impeded autolysosomal flux, leading to Yap accumulation and malignant transformation. Conversely, oral administration of cholestyramine to sequestrate intestinal endotoxin and bile acids resumed autolysosomal flux for Yap degradation and attenuated metastatic incidence. Conversely, chloroquine treatment impaired autolysosomal flux and exacerbated malignance, showing jeopardization of p62/ Sqxtm1 turnover, leading to Yap accumulation, which is also consistent with overexpression of cystatin A (CSTA) in situ with pancreatic cancer cells and metastatic tumor. At cellular levels, chenodeoxycholic acid or LPS treatment activated the ligand–receptor-mediated AKT-mTOR pathway, resulting in autophagy-lysosomal stress for YAP accumulation and cellular dissemination. Thus, this work indicates a potential new strategy for intervention of pancreatic metastasis through sequestration of intestinal acidic toxins by oral administration of cationic resins.

Lycopene Inhibits IL-6 Expression by Upregulating NQO1 and HO-1 via Activation of Nrf2 in Ethanol/Lipopolysaccharide-Stimulated Pancreatic Acinar Cells

In alcoholic pancreatitis, alcohol increases gut permeability, which increases the penetration of endotoxins, such as lipopolysaccharides (LPS). LPS act as clinically significant triggers to increase pancreatic damage in alcoholic pancreatitis. Ethanol or LPS treatment increases reactive oxygen species (ROS) production in pancreatic acinar cells. ROS induce inflammatory cytokine production in pancreatic acinar cells, leading to pancreatic inflammation. The nuclear erythroid-2-related factor 2 (Nrf2) pathway is activated as a cytoprotective response to oxidative stress, and induces the expression of NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). Lycopene exerts anti-inflammatory and antioxidant effects in various cells. We previously showed that lycopene inhibits NADPH oxidase to reduce ROS and IL-6 levels, and zymogene activation in ethanol or palmitoleic acid-treated pancreatic acinar cells. In this study, we examined whether lycopene inhibits IL-6 expression by activating the Nrf2/NQO1-HO-1 pathway, and reducing intracellular and mitochondrial ROS levels, in ethanol and LPS-treated pancreatic AR42J cells. Lycopene increased the phosphorylated and nuclear-translocated Nrf2 levels by decreasing the amount of Nrf2 sequestered in the cytoplasm via a complex formation with Kelch-like ECH1-associated protein 1 (Keap1). Using exogenous inhibitors targeting Nrf2 and HO-1, we showed that the upregulation of activated Nrf2 and HO-1 results in lycopene-induced suppression of IL-6 expression and ROS production. The consumption of lycopene-rich foods may prevent the development of ethanol and LPS-associated pancreatic inflammation by activating Nrf2-mediated expression of NQO1 and HO-1, thereby decreasing ROS-mediated IL-6 expression in pancreatic acinar cells.

Epigenetic changes in inflammatory genes and the protective effect of cooked rhubarb on pancreatic tissue of rats with chronic alcohol exposure

Chronic alcohol consumption, which is observed worldwide, can damage pancreatic tissue and promote pancreatitis. Rhubarb is a widely used traditional Chinese herbal medicine for treating pancreatitis in China. However, few pharmacological studies have investigated its epigenetic regulation. In this study, we investigated whether chronic exposure to alcohol can alter inflammatory gene expression and the epigenetic regulation effect of cooked rhubarb in the pancreatic tissue of rats. First, changes in inflammatory cytokine DNA methylation (IL-10, IL-1α, TNF-α, NF-κB and TGF-β) were detected in pancreatic tissue of Sprague-Dawley rats with varying alcohol exposure times (4, 6, 8, or 12 weeks), and then with varying doses of cooked rhubarb treatment (3, 6, or 12 g/day). DNA methylation levels, related RNA concentrations and protein expression of specific inflammatory cytokines, and histopathological score were analysed in pancreatic tissue of Sprague-Dawley rats. The results showed that chronic alcohol exposure (8 weeks) reduced the level of IL-1α DNA methylation and increased its protein expression in acinar cells (P < 0.05). In the acinar cells, the level of IL-10 DNA methylation increased, resulting in a reduction of protein expression (P < 0.05). Simultaneously, chronic alcohol exposure increased the pathological damage to the pancreas (P < 0.05). Finally, cooked rhubarb treatment (3 g/kg/day) effectively alleviated these changes in pancreatic tissue from chronic alcohol exposure (P < 0.05). These results indicate that chronic exposure to alcohol leads to changes in DNA methylation and protein expression of inflammatory genes, and cooked rhubarb may have a protective effect on the pancreatic tissue of rats.

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.

Pancreatic stellate cells - rising stars in pancreatic pathologies

Pluripotent pancreatic stellate cells (PSCs) receive growing interest in past decades. Two types of PSCs are recognized –vitamin A accumulating quiescent PSCs and activated PSCs- the main producents of extracellular matrix in pancreatic tissue. PSCs plays important role in pathogenesis of pancreatic fibrosis in pancreatic cancer and chronic pancreatitis. PSCs are intensively studied as potential therapeutical target because of their important role in developing desmoplastic stroma in pancreatic cancer. There also exists evidence that PSC are involved in other pathologies like type-2 diabetes mellitus. This article brings brief characteristics of PSCs and recent advances in research of these cells.

The Role of Phosphate in Alcohol-Induced Experimental Pancreatitis

BACKGROUND & AIMS

Heavy alcohol consumption is a common cause of acute pancreatitis; however, alcohol abuse does not always result in clinical pancreatitis. As a consequence, the factors responsible for alcohol-induced pancreatitis are not well understood. In experimental animals, it has been difficult to produce pancreatitis with alcohol. Clinically, alcohol use predisposes to hypophosphatemia, and hypophosphatemia has been observed in some patients with acute pancreatitis. Because of abundant protein synthesis, the pancreas has high metabolic demands, and reduced mitochondrial function leads to organelle dysfunction and pancreatitis. We proposed, therefore, that phosphate deficiency might limit adenosine triphosphate synthesis and thereby contribute to alcohol-induced pancreatitis.

METHODS

Mice were fed a low-phosphate diet (LPD) before orogastric administration of ethanol. Direct effects of phosphate and ethanol were evaluated in vitro in isolated mouse pancreatic acini.

RESULTS

LPD reduced serum phosphate levels. Intragastric administration of ethanol to animals maintained on an LPD caused severe pancreatitis that was ameliorated by phosphate repletion. In pancreatic acinar cells, low-phosphate conditions increased susceptibility to ethanol-induced cellular dysfunction through decreased bioenergetic stores, specifically affecting total cellular adenosine triphosphate and mitochondrial function. Phosphate supplementation prevented ethanol-associated cellular injury.

CONCLUSIONS

Phosphate status plays a critical role in predisposition to and protection from alcohol-induced acinar cell dysfunction and the development of acute alcohol-induced pancreatitis. This finding may explain why pancreatitis develops in only some individuals with heavy alcohol use and suggests a potential novel therapeutic approach to pancreatitis. Finally, an LPD plus ethanol provides a new model for studying alcohol-associated pancreatic injury.

Dahuang Danshen Decoction Inhibits Pancreatic Fibrosis by Regulating Oxidative Stress and Endoplasmic Reticulum Stress

Background

In Traditional Chinese Medicine (TCM), Dahuang Danshen decoction (DD) is used to treat pancreatic fibrosis. Pancreatic fibrosis is a typical manifestation of chronic pancreatitis (CP), which affects the digestive system. The therapeutic mechanisms of DD in pancreatic fibrosis are unclear.

Aim

This study aimed to investigate the regulatory mechanisms of DD on oxidative stress and endoplasmic reticulum stress in CP.

Materials and Methods

Experimental rats were intraperitoneally injected with 500 mg/kg BW of diethyldithiocarbamate (DDC) twice a week for six weeks to induce CP. At the same time, DD was administered orally at daily doses of 1.37 g/kg BW, 2.74 g/kg BW, and 5.48 g/kg BW to evaluate its treatment effects on CP. After all treatments, pancreatic tissues were harvested and subjected to H&E staining. Transmission electron microscopy (TEM) was also performed to show the endoplasmic reticulum structure in the pancreatic tissues. Immunohistochemistry was used to detect the α-SMA expression level in the pancreatic tissues. Metabolomics analysis of the serum and proteomics analysis of the pancreatic tissues were performed to reveal the changes of endogenous metabolites and proteins, respectively. Concentrations of GSH, MDA, SOD, ROS, col-1, and col-3 were determined using corresponding kits. The western blotting method was used to determine the protein levels of Keap-1, HO-1, NQO1, Nrf2, GRP, JNK, and caspase 12. The pancreatic mRNA levels of NQO1, GPX1, HO-1, GST-π, GRP, JNK, and caspase 12 were also determined by quantitative PCR. The interactions between TCM components and Keap-1 were investigated by molecular docking modeling.

Results

The pathohistological results demonstrated that DD could ameliorate DDC-induced CP in vivo, indicated by reduction of α-SMA, col-1, col-3, TNF-α, and IL-6. DD increased serum levels of GSH and SOD but reduced pancreatic ROS. DD decreased cytoplasmic Keap-1 and increased Nrf2 nuclear localization. Correspondingly, DD increased the expression levels of Nrf2 downstream antioxidant genes NQO1, GPX1, HO-1, and GST-π. DD also decreased ERS hallmarks caspase 12 cleavage and GRP expression. Eventually, DD inhibited PSC activation by reducing JNK phosphorylation and MMK-3/p38 expression. Molecular docking analysis showed that salvianolic acid B and emodin had a good binding affinity toward Keap-1.

Conclusions

These results demonstrated that DD could ameliorate the oxidative and endoplasmic reticulum stress through releasing Nrf2 from Keap-1 binding and inducing the downstream antioxidant enzymes. As a result, DD could thwart pancreatic fibrosis by inhibiting PSCs activation, which was induced by OS and ERS through JNK and MMK3/p38 pathways.

Alcohol use disorder and the gut

Acute and chronic gastrointestinal problems are common in the setting of excessive alcohol use, and excessive alcohol use is associated with injury to all parts of the gastrointestinal tract. There is mounting evidence of gastrointestinal injury and increased cancer risk even from moderate alcohol consumption. The major causes of alcohol-related morbidity and mortality within the gastrointestinal system are liver disease, pancreatitis and gastrointestinal cancer. Other alcohol-related intestinal dysfunction is common but not life-threatening, leading to diarrhoea, malabsorption and nutritional deficiencies. This review describes non-neoplastic and neoplastic alcohol-related disorders of the gastrointestinal tract, omitting the liver, which has been reviewed elsewhere.

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.

What Do We Currently Know about the Pathophysiology of Alcoholic Pancreatitis: A Brief Review

BACKGROUND

Alcoholic pancreatitis is a serious medical concern worldwide and remains to be one of the common causes of pancreatic disease.

SUMMARY

While alcohol consumption causes direct damage to pancreatic tissue, only a small percentage of active drinkers will develop pancreatitis. An explanation of this phenomenon is probably that alcohol increases pancreatic vulnerability to damage; however, the simultaneous presence of additional risk factors and pancreatic costressors is required to increase the risk of pancreatitis and its complications caused by alcohol misuse. Recently, a number of important genetic as well as environmental factors influencing the risk of alcoholic pancreatitis have been described.

KEY MESSAGES

In brief, this review reports established factors for the development of alcoholic pancreatitis and summarizes recent progress made in basic and clinical research.

cis-4-[18F]fluoro-L-proline Molecular Imaging Experimental Liver Fibrosis

Introduction: Early-stage liver fibrosis is potentially reversible, but difficult to diagnose. Clinical management would be enhanced by the development of a non-invasive imaging technique able to identify hepatic injury early, before end-stage fibrosis ensues. The analog of the amino acid proline, cis-4-[¹⁸F]fluoro-L-proline ([¹⁸F]fluoro-proline), which targets collagenogenesis in hepatic stellate cells (HSC), was used to detect fibrosis.

Methods: Acute steatohepatitis was induced in experimental animals by liquid ethanol diet for 8 weeks, intra-gastric binge feedings every 10th day along with lipopolysaccharide (LPS) injection. The control animals received control diet for 8 weeks and an equivalent volume of saline on the same schedule as the acute steatohepatitis model. First, in vitro cellular experiments were carried out to assess [³H]proline uptake by HSC, hepatocytes and Kupffer cells derived from rats with acute steatohepatitis (n = 14) and controls (n = 14). Next, ex vivo liver experiments were done to investigate unlabeled proline-mediated collagen synthesis and its associated proline transporter expression in acute steatohepatitis (n = 5) and controls (n = 5). Last, in vivo dynamic and static [¹⁸F]fluoro-proline micro-PET/CT imaging was performed in animal models of acute steatohepatitis (n = 7) and control (n = 7) mice.

Results: [³H]proline uptake was 5-fold higher in the HSCs of steatohepatitis rats than controls after incubation of up to 60 min. There was an excellent correlation between [³H]proline uptake and liver collagen expression (r-value > 0.90, p < 0.05). Subsequent liver tissue studies demonstrated 2–3-fold higher proline transporter expression in acute steatohepatitis animals than in controls, and proline-related collagen synthesis was blocked by this transporter inhibitor. In vivo micro-PET/CT studies with [¹⁸F]fluoro-proline showed 2–3-fold higher uptake in the livers of acute steatohepatitis mice than in controls. There was an excellent correlation between [¹⁸F]fluoro-proline uptake and liver collagen expression in the livers of acute steatohepatitis mice (r-value = 0.97, p < 0.001).

Conclusion: [¹⁸F]fluoro-proline localizes in the liver and correlates with collagenogenesis in acute steatohepatitis with a signal intensity that is sufficiently high to allow imaging with micro-PET/CT. Thus, [¹⁸F]fluoro-proline could serve as a PET imaging biomarker for detecting early-stage liver fibrosis.

Recent Advances in Understanding the Complexity of Alcohol-Induced Pancreatic Dysfunction and Pancreatitis Development

Chronic excessive alcohol use is a well-recognized risk factor for pancreatic dysfunction and pancreatitis development. Evidence from in vivo and in vitro studies indicates that the detrimental effects of alcohol on the pancreas are from the direct toxic effects of metabolites and byproducts of ethanol metabolism such as reactive oxygen species. Pancreatic dysfunction and pancreatitis development are now increasingly thought to be multifactorial conditions, where alcohol, genetics, lifestyle, and infectious agents may determine the initiation and course of the disease. In this review, we first highlight the role of nonoxidative ethanol metabolism in the generation and accumulation of fatty acid ethyl esters (FAEEs) that cause multi-organellar dysfunction in the pancreas which ultimately leads to pancreatitis development. Further, we discuss how alcohol-mediated altered autophagy leads to the development of pancreatitis. We also provide insights into how alcohol interactions with other co-morbidities such as smoking or viral infections may negatively affect exocrine and endocrine pancreatic function. Finally, we present potential strategies to ameliorate organellar dysfunction which could attenuate pancreatic dysfunction and pancreatitis severity.

Susceptibility Factors and Cellular Mechanisms Underlying Alcoholic Pancreatitis

Alcohol is a major cause of acute and chronic pancreatitis. There have been some recent advances in the understanding of the mechanisms underlying alcoholic pancreatitis, which include perturbation in mitochondrial function and autophagy and ectopic exocytosis, with some of these cellular events involving membrane fusion soluble N-ethylmaleimide-sensitive factor receptor protein receptor proteins. Although new insights have been unraveled recently, the precise mechanisms remain complex, and their finer details have yet to be established. The overall pathophysiology of pancreatitis involves not only the pancreatic acinar cells but also the stellate cells and duct cells. Why only some are more susceptible to pancreatitis and with increased severity, while others are not, would suggest that there may be undefined protective factors or mechanisms that enhance recovery and regeneration after injury. Furthermore, there are confounding influences of lifestyle factors such as smoking and diet, and genetic background. Whereas alcohol and smoking cessation and a generally healthy lifestyle are intuitively the advice given to these patients afflicted with alcoholic pancreatitis in order to reduce disease recurrence and progression, there is as yet no specific treatment. A more complete understanding of the pathogenesis of pancreatitis from which novel therapeutic targets could be identified will have a great impact, particularly with the stubbornly high fatality (>30%) of severe pancreatitis. This review focuses on the susceptibility factors and underlying cellular mechanisms of alcohol injury on the exocrine pancreas.

ADAM17-Mediated Reduction in CD14++CD16+ Monocytes ex vivo and Reduction in Intermediate Monocytes With Immune Paresis in Acute Pancreatitis and Acute Alcoholic Hepatitis

Impaired immune responses and increased susceptibility to infection characterize acute inflammatory conditions such as pancreatitis and alcoholic hepatitis and are major causes of morbidity and mortality. However, the mechanisms that drive this apparent immune paresis remain poorly understood. Monocytes mediate host responses to damage and pathogens in health and disease, and three subsets of monocytes have been defined based on CD14 and CD16 expression. We sought to determine the changes in monocyte subsets in acute pancreatitis (AP) and acute alcoholic hepatitis (AAH), together with functional consequences and mechanisms that underlie this change. Peripheral blood mononuclear cells (PBMCs) from patients with AP or AAH were compared with healthy controls. Monocyte subsets were defined by HLA-DR, CD14, and CD16 expression. Changes in surface and intracellular protein expression and phosphorylation were determined by flow cytometry. Phenotype and function were assessed following stimulation with lipopolysaccharide (LPS) or other agonists in the presence of specific inhibitors of TNFα and a disintegrin and metalloproteinase 17 (ADAM17). Patients with AP and AAH had reduced CD14⁺⁺CD16⁺ intermediate monocytes compared to controls. Reduction of intermediate monocytes was recapitulated ex vivo by stimulating healthy control PBMCs with Toll-like receptor (TLR) agonists LPS, flagellin or polyinosilic:polycytidylic acid (poly I:C). Stimulation caused shedding of CD14 and CD16, which could be reversed using the ADAM17 inhibitor, TMI005 but not direct inhibitors of TNFα, a known ADAM17-target. Culturing PBMCs from healthy controls resulted in expansion of intermediate monocytes, which did not occur when LPS was in the culture medium. Cultured intermediate monocytes showed reduced expression of CX₃CR1, CCR2, TLR4, and TLR5. We found reduced migratory responses, intracellular signaling and pro-inflammatory cytokine production, and increased expression of IL-10. Stimulation with TLR agonists results in ADAM17-mediated shedding of phenotypic markers from CD16⁺ monocytes, leading to apparent “loss” of intermediate monocytes. Reduction in CD14⁺⁺CD16⁻ monocytes and increased CD14⁺⁺CD16⁺ is associated with altered responses in functional assays ex vivo. Patients with AP and AAH had reduced proportions of CD14⁺⁺CD16⁺ monocytes and reduced phosphorylation of NFκB and IL-6 production in response to bacterial LPS. Together, these processes may contribute to the susceptibility to infection observed in AP and AAH.

Epigenetic Mechanisms of Pancreatobiliary Fibrosis

PURPOSE OF REVIEW

The goal of this manuscript is to review the current literature related to fibrogenesis in the pancreatobiliary system and how this process contributes to pancreatic and biliary diseases. In particular, we seek to define the current state of knowledge regarding the epigenetic mechanisms that govern and regulate tissue fibrosis in these organs. A better understanding of these underlying molecular events will set the stage for future epigenetic therapeutics.

RECENT FINDINGS

We highlight the significant advances that have been made in defining the pathogenesis of pancreatobiliary fibrosis as it relates to chronic pancreatitis, pancreatic cancer, and the fibro-obliterative cholangiopathies. We also review the cell types involved as well as concepts related to epithelial-mesenchymal crosstalk. Furthermore, we outline important signaling pathways (e.g., TGFβ) and diverse epigenetic processes (i.e., DNA methylation, non-coding RNAs, histone modifications, and 3D chromatin remodeling) that regulate fibrogenic gene networks in these conditions. We review a growing body of scientific evidence linking epigenetic regulatory events to fibrotic disease states in the pancreas and biliary system. Advances in this understudied area will be critical toward developing epigenetic pharmacological approaches that may lead to more effective treatments for these devastating and difficult to treat disorders.

Induction of Pancreatic Inflammation Accelerates Pancreatic Tumorigenesis in Mice

Pancreatitis is a major risk factor for the development of pancreatic cancer. In genetically engineered mouse models, induction of pancreatic inflammation dramatically accelerates oncogenic KRas-induced fibrosis, precancerous PanIN formation, and tumorigenesis. Here we describe simple methods of secretagogue-induced experimental acute and chronic pancreatitis, the most commonly used pancreatitis models, and their applications in pancreatic cancer research. Additionally, the preparation of primary pancreatic acinar cells is introduced. Primary acinar cells can be used to study the early events of pancreatic inflammation and pancreatic acinar-to-ductal (ADM) metaplasia.

Pancreatic Stellate Cells Serve as a Brake Mechanism on Pancreatic Acinar Cell Calcium Signaling Modulated by Methionine Sulfoxide Reductase Expression

Although methionine sulfoxide reductase (Msr) is known to modulate the activity of multiple functional proteins, the roles of Msr in pancreatic stellate cell physiology have not been reported. In the present work we investigated expression and function of Msr in freshly isolated and cultured rat pancreatic stellate cells. Msr expression was determined by RT-PCR, Western blot and immunocytochemistry. Msr over-expression was achieved by transfection with adenovirus vectors. Pancreatic stellate cells were co-cultured with pancreatic acinar cells AR4-2J in monolayer culture. Pancreatic stellate and acinar cell function was monitored by Fura-2 calcium imaging. Rat pancreatic stellate cells were found to express MsrA, B1, B2, their expressions diminished in culture. Over-expressions of MsrA, B1 or B2 were found to enhance ATP-stimulated calcium increase but decreased reactive oxygen species generation and lipopolysaccharide-elicited IL-1 production. Pancreatic stellate cell-co-culture with AR4-2J blunted cholecystokinin- and acetylcholine-stimulated calcium increases in AR4-2J, depending on acinar/stellate cell ratio, this inhibition was reversed by MsrA, B1 over-expression in stellate cells or by Met supplementation in the co-culture medium. These data suggest that Msr play important roles in pancreatic stellate cell function and the stellate cells may serve as a brake mechanism on pancreatic acinar cell calcium signaling modulated by stellate cell Msr expression.

Dietary pomegranate supplement alleviates murine pancreatitis by modulating Nrf2-p21 interaction and controlling apoptosis to survival switch

Dietary supplementation of polyphenol-rich pomegranate extract (POMx) has been shown to have anti-oxidant and anti-inflammatory activities. Here, we evaluate the efficacy of POMx in mitigating pancreatitis in mice and provide a mechanistic outline of the process. Age-matched male Swiss albino mice were injected with Lipopolysaccharide (LPS) and given POMx supplement alone or in combination with LPS. After 4 weeks of treatment histological scoring for pancreatic edema and vacuolization was performed. Serum insulin levels were estimated and the glucose tolerance test (IPGTT) data revealed that POMx reduced inflammation induced hyperglycemia in mice. Analysis of TLR4, IκB expression, and NF-κB nuclear translocation, and concentrations of IL-6 and TNFα showed that POMx is able to modulate the molecular instigators of inflammatory responses. Annexin V assay indicated that POMx protects against inflammation-mediated apoptosis in the pancreas. Expression profile of SAPK/JNK pathway, p53, Bax, Bcl-2 and Caspase-3 validate an apoptotic to survival shift in POMx treatment group. Co-immunoprecipitation studies show that POMx stabilizes p21 and Nrf2 interaction and increases its nuclear translocation. The study also proves that the nuclear fraction of Nrf2 is able to bind to the Bcl-2 promoter and activate an anti-apoptotic program. The findings of our study underline an anti-inflammatory, anti-oxidative and anti-apoptotic role of POMx and provide a mechanistic idea of how POMx confers protection during pancreatitis.

Ginsenoside Rd ameliorates colitis by inducing p62-driven mitophagy-mediated NLRP3 inflammasome inactivation in mice

Previous studies reported that Ginsenoside Rd (Rd) had anti-inflammatory and anti-cancer effects. However, the molecular mechanism underlying the inhibition effect of Rd on colitis in mice hasn't been clarified clearly. Here, in our study, we detected the effects of Rd on dextran sulfate sodium (DSS)-induced murine colitis, and found that oral administration of Rd dose-dependently alleviated DSS-induced body weight loss, colon length shortening and colonic pathological damage with lower myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) activities and higher glutathione level. In addition, the production of pro-inflammatory cytokines (IL-1β, TNF-a and IL-6) in both serum and colonic tissues were significantly down-regulated by Rd administration. The activation of NLRP3 inflammasome was also suppressed in Rd-treated group, resulting in reduced caspase-1 production and IL-1β secretion. In vitro, Rd remarkably inhibited NLRP3 inflammasome activation which was mostly dependent on the mitochondrial translocation of p62 and mitophagy. Importantly, Rd-driven inhibition of the NLRP3 inflammasome was significantly blocked by various autophagy inhibitors. Furthermore, upregulation of AMPK/ULK1 signaling pathway accounted for Rd-induced autophagy, which was also seen in vivo. In conclusion, our results demonstrated the function of Rd on the inhibition NLRP3 inflammasome and its potential application for the treatment of NLRP3-associated diseases.

Genetically induced vs. classical animal models of chronic pancreatitis: a critical comparison

Chronic pancreatitis (CP) is an utmost complex disease that is pathogenetically linked to pancreas-intrinsic ( e.g., duct obstruction), environmental-toxic ( e.g., alcohol, smoking), and genetic factors. Studying such a complex disease naturally requires validated experimental models. In the past 2 decades, the various animal models of CP usually addressed either the pancreas-intrinsic ( e.g., the caerulein model), the environmental-toxic ( e.g., diet-induced models), or the genetic component of CP. As such, these models were far from mirroring CP in its full spectrum, and the correct choice of models was vital for valid scientific conclusions on CP. The quest for mechanistic, genetic models gave rise to models based on gene modification and transgene insertion, such as the PRSS1 and the IL-1β/IL-1β models. Recently, we witnessed the development of highly exciting models that rely on the importance of autophagy in CP, that is, the murine pancreas-specific Atg5 and LAMP2 knockout models. Today, critical comparison of these several models is more important than ever for guiding research on CP in an efficient direction. The present review outlines the characteristics of the new genetic models in comparison with the well-known classic models for CP, notes the caveats in the choice of models, and also indicates novel directions for model development.-Klauss, S., Schorn, S., Teller, S., Steenfadt, H., Friess, H., Ceyhan, G. O., Demir, I. K. Genetically induced vs. classical animal models of chronic pancreatitis: a critical comparison.

Characterization of the duodenal bacterial microbiota in patients with pancreatic head cancer vs. healthy controls

An increasing number of reports have demonstrated that there is an association between the presence of pathogenic microorganisms and pancreatic cancer. However, the role of the duodenal microbiota in pancreatic carcinogenesis remains unknown. In this study, duodenal mucosal microbiota was analyzed in 14 patients with pancreatic head cancer and 14 healthy controls using 16S rRNA gene pyrosequencing methods. Plasma endotoxin activity and the concentrations of the proinflammatory cytokine IL-6 and C-reactive protein (CRP) were measured in blood samples. The urea breath test was used to detect Helicobacter pylori infections. Endoscopic duodenal mucosal biopsies were evaluated by histological examinations. Statistical comparisons of inflammatory factors revealed significantly higher levels of CRP and IL-6 in the pancreatic cancer group as compared to healthy controls. Patients with pancreatic cancer also had a higher incidence of H. pylori infections and showed mucosal changes, including villous abnormalities and diffuse inflammatory cell infiltration in the lamina propria. The sequences analysis showed that based on linear discriminant analysis effect size (LEfSe) analysis at the genus level, Acinetobacter, Aquabacterium, Oceanobacillus, Rahnella, Massilia, Delftia, Deinococcus, and Sphingobium were more abundant in the duodenal mucosa of pancreatic cancer patients, whereas the duodenal microbiotas of healthy controls were enriched with Porphyromonas, Paenibacillus, Enhydrobacter, Escherichia, Shigella, and Pseudomonas. These results reveal a picture of duodenal microbiota in pancreatic head cancer patients that could be useful in future trials investigating the role of gut microbiota in pancreatic cancer.

Lipopolysaccharide enhances TGF-β1 signalling pathway and rat pancreatic fibrosis

Pancreatic stellate cells (PSCs) play a critical role in fibrogenesis during alcoholic chronic pancreatitis (ACP). Transforming growth factor-beta1 (TGF-β1) is a key regulator of extracellular matrix production and PSC activation. Endotoxin lipopolysaccharide (LPS) has been recognized as a trigger factor in the pathogenesis of ACP. This study aimed to investigate the mechanisms by which LPS modulates TGF-β1 signalling and pancreatic fibrosis. Sprague-Dawley rats fed with a Lieber-DeCarli alcohol (ALC) liquid diet for 10 weeks with or without LPS challenge during the last 3 weeks. In vitro studies were performed using rat macrophages (Mφs) and PSCs (RP-2 cell line). The results showed that repeated LPS challenge resulted in significantly more collagen production and PSC activation compared to rats fed with ALC alone. LPS administration caused overexpression of pancreatic TLR4 or TGF-β1 which was paralleled by an increased number of TLR4-positive or TGF-β1-positive Mφs or PSCs in ALC-fed rats. In vitro, TLR4 or TGF-β1 production in Mφs or RP-2 cells was up-regulated by LPS. LPS alone or in combination with TGF-β1 significantly increased type I collagen and α-SMA production and Smad2 and 3 phosphorylation in serum-starved RP-2 cells. TGF-β pseudoreceptor BAMBI production was repressed by LPS, which was antagonized by Si-TLR4 RNA or by inhibitors of MyD88/NF-kB. Additionally, knockdown of Bambi with Si-Bambi RNA significantly increased TGF-β1 signalling in RP-2 cells. These findings indicate that LPS increases TGF-β1 production through paracrine and autocrine mechanisms and that LPS enhances TGF-β1 signalling in PSCs by repressing BAMBI via TLR4/MyD88/NF-kB activation.

Phytoceuticals in Acute Pancreatitis: Targeting the Balance between Apoptosis and Necrosis

Despite recent advances in understanding the complex pathogenesis of pancreatitis, the management of the disease remains suboptimal. The use of phytoceuticals (plant-derived pleiotropic multitarget molecules) represents a new research trend in pancreatology. The purpose of this review is to discuss the phytoceuticals with pancreatoprotective potential in acute pancreatitis and whose efficacy is based, at least in part, on their capacity to modulate the acinar cell death. The phytochemicals selected, belonging to such diverse classes as polyphenols, flavonoids, lignans, anthraquinones, sesquiterpene lactones, nitriles, and alkaloids, target the balance between apoptosis and necrosis. Activation of apoptosis via various mechanisms (e.g., inhibition of X-linked inhibitor of apoptosis proteins by embelin, upregulation of FasL gene expression by resveratrol) and/or inhibition of necrosis seem to represent the essential key for decreasing the severity of the disease. Apart from targeting the apoptosis/necrosis balance, the phytochemicals displayed other specific protective activities: inhibition of inflammasome (e.g., rutin), suppression of neutrophil infiltration (e.g., ligustrazine, resveratrol), and antioxidant activity. Even though many of the selected phytoceuticals represent a promising therapeutic alternative, there is a shortage of human evidence, and further studies are required to provide solid basis to justify their use in the treatment of pancreatitis.

The Combination of Alcohol and Cigarette Smoke Induces Endoplasmic Reticulum Stress and Cell Death in Pancreatic Acinar Cells

BACKGROUND & AIMS

Smoking, an independent risk factor for pancreatitis, accelerates the development of alcoholic pancreatitis. Alcohol feeding of mice induces up-regulation of spliced X-box binding protein 1 (XBP1s), which regulates the endoplasmic reticulum (ER) unfolded protein response and promotes cell survival upon ER stress. We examined whether smoking affects the adaptive mechanisms induced by alcohol and accelerates disorders of the ER in pancreatic acinar cells.

METHODS

We studied the combined effects of ethanol (EtOH) and cigarette smoke extract (CSE) on ER stress and cell death responses in mouse and human primary acini and the acinar cell line AR42J. Cells were incubated with EtOH (50 mmol/L), CSE (20-40 μg/mL), or both (CSE+EtOH), and analyzed by immunoblotting, quantitative reverse-transcription polymerase chain reaction, and cell death assays. Some cells were incubated with MKC-3946, an inhibitor of endoplasmic reticulum to nucleus signaling 1 (ERN1, also called IRE1) that blocks XBP1s formation. Male Sprague-Dawley rats were fed isocaloric amounts of an EtOH-containing (Lieber-DeCarli) or control diet for 11 weeks and exposed to cigarette smoke or room air in an exposure chamber for 2 hours each day. During the last 3 weeks, a subset of rats received intravenous injections of lipopolysaccharide (LPS, 3 mg/kg per week) to induce pancreatitis or saline (control). Pancreatic tissues were collected and analyzed by histology and immunostaining techniques.

RESULTS

In AR42J and primary acini, CSE+EtOH induced cell death (necrosis and apoptosis), but neither agent alone had this effect. Cell death was associated with a significant decrease in expression of XBP1s. CSE+EtOH, but neither agent alone, slightly decreased adenosine triphosphate levels in AR42J cells, but induced oxidative stress and sustained activation (phosphorylation) of eukaryotic translation initiation factor 2 alpha kinase 3 (EIF2AK3, also called PERK) and increased protein levels of DNA damage inducible transcript 3 (DDIT3, also called CHOP). CHOP regulates transcription to promote apoptosis. Incubation of AR42J or primary mouse or human acinar cells with MKC-3946 reduced expression of XBP1s, increased levels of CHOP, and induced cell death. In rats fed an EtOH diet, exposure to cigarette smoke increased ER stress in acinar cells and sensitized the pancreas to LPS-induced pathology.

CONCLUSIONS

Cigarette smoke promotes cell death and features of pancreatitis in EtOH-sensitized acinar cells by suppressing the adaptive unfolded protein response signaling pathway. It also activates ER stress pathways that promote acinar cell death.

Effects of ω-3 Fatty Acids on Toll-like Receptor 4 and Nuclear Factor κB p56 in the Pancreas of Rats With Severe Acute Pancreatitis

OBJECTIVES

The aims of this study were to determine the effects of ω-3 fatty acids (ω-3FAs) on the Toll-like receptor 4 (TLR4)/nuclear factor κB p56 (NF-κBp56) signaling pathway in the pancreas of rats with severe acute pancreatitis (SAP).

METHODS

Sixty-four Sprague-Dawley rats were randomly divided into 4 groups: the control, SAP-saline, SAP-soybean oil, and SAP-ω-FA groups. Severe acute pancreatitis was induced by the retrograde infusion of sodium taurocholate into the pancreatic duct. The expression of TLR4 and NF-κBp56 in the pancreas was evaluated by immunohistochemistry and Western blot analysis. The levels of the proinflammatory cytokines interleukin 6 and tumor necrosis factor α in the pancreas were measured by enzyme-linked immunosorbent assays.

RESULTS

Toll-like receptor 4, NF-κBp56, and inflammatory cytokine expression in the pancreas was increased significantly in the SAP group compared with that in the control group (P < 0.05), but was significantly decreased in the ω-3FA group compared with that in the soybean oil group at 24 and 48 hours (P < 0.05).

CONCLUSIONS

Our results suggest that during the initial stage of SAP ω-3FAs could efficiently lower the inflammatory response by activating the TLR4/NF-κBp56 signaling pathway.

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.

Mathematical model of chronic pancreatitis

Chronic pancreatitis (CP) is a progressive inflammatory disease of the pancreas, leading to its fibrotic destruction. There are currently no drugs that can stop or slow the progression of the disease. The etiology of the disease is multifactorial, whereas recurrent attacks of acute pancreatitis are thought to precede the development of CP. A better understanding of the pathology of CP is needed to facilitate improved diagnosis and treatment strategies for this disease. The present paper develops a mathematical model of CP based on a dynamic network that includes macrophages, pancreatic stellate cells, and prominent cytokines that are present at high levels in the CP microenvironment. The model is represented by a system of partial differential equations. The model is used to explore in silico potential drugs that could slow the progression of the disease, for example infliximab (anti-TNF-[Formula: see text]) and tocilizumab or siltuximab (anti-IL-6/IL-6R).

Pathogenic mechanisms of pancreatitis

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

Dietary Factors Reduce Risk of Acute Pancreatitis in a Large Multiethnic Cohort

BACKGROUND & AIMS

Pancreatitis is a source of substantial morbidity and health cost in the United States. Little is known about how diet might contribute to its pathogenesis. To characterize dietary factors that are associated with risk of pancreatitis by disease subtype, we conducted a prospective analysis of 145,886 African Americans, Native Hawaiians, Japanese Americans, Latinos, and whites in the Multiethnic Cohort.

METHODS

In the Multiethnic Cohort (age at baseline, 45-75 y), we identified cases of pancreatitis using hospitalization claim files from 1993 through 2012. Patients were categorized as having gallstone-related acute pancreatitis (AP) (n = 1210), AP not related to gallstones (n = 1222), or recurrent AP or suspected chronic pancreatitis (n = 378). Diet information was obtained from a questionnaire administered when the study began. Associations were estimated by hazard ratios and 95% confidence intervals using Cox proportional hazard models adjusted for confounders.

RESULTS

Dietary intakes of saturated fat (P trend = .0011) and cholesterol (P trend = .0008) and their food sources, including red meat (P trend < .0001) and eggs (P trend = .0052), were associated positively with gallstone-related AP. Fiber intake, however, was associated inversely with gallstone-related AP (P trend = .0005) and AP not related to gallstones (P trend = .0035). Vitamin D, mainly from milk, was associated inversely with gallstone-related AP (P trend = .0015), whereas coffee consumption protected against AP not related to gallstones (P trend < .0001). With the exception of red meat, no other dietary factors were associated with recurrent acute or suspected chronic pancreatitis.

CONCLUSIONS

Associations between dietary factors and pancreatitis were observed mainly for gallstone-related AP. Interestingly, dietary fiber protected against AP related and unrelated to gallstones. Coffee drinking protected against AP not associated with gallstones. Further studies are warranted to confirm our findings.

Dysregulation of signaling pathways associated with innate antibacterial immunity in patients with pancreatic cancer

Disorders of innate antibacterial response are of fundamental importance in the development of gastrointestinal cancers, including pancreatic cancer. Multi-regulatory properties of the Toll-like receptors (TLRs) (e.g., regulation of proliferation, the activity of NF-κB, gene transcription of apoptosis proteins, regulation of angiogenesis, HIF-1α protein expression) are used in experimental studies to better understand the pathogenesis of pancreatic cancer, for early diagnosis, and for more effective therapeutic intervention. There are known numerous examples of TLR agonists (e.g., TLR2/5 ligands, TLR6, TLR9) of antitumor effect. The direction of these studies is promising, but a small number of them does not allow for an accurate assessment of the impact of TLR expression disorders, proteins of these signaling pathways, or attempts to block or stimulate them, on the results of treatment of pancreatic cancer patients. It is known, however, that the expression disorders of proteins of innate antibacterial response signaling pathways occur not only in tumor tissue but also in peripheral blood leukocytes of pancreatic cancer patients (e.g., increased expression of TLR4, NOD1, TRAF6), which is one of the most important factors facilitating further tumor development. This review mainly focuses on the genetic aspects of signaling pathway disorders associated with innate antibacterial response in the pathogenesis and diagnosis of pancreatic cancer.

Retrospective electron microscopy: Preservation of fine structure by freezing and aldehyde fixation

For many years it has been believed that ultrastructural analysis by transmission electron microscopy (TEM) is not possible using frozen tissues. We have developed a TEM method that allows the evaluation of organelles using pancreatic tissue that was previously liquid nitrogen snap-frozen and stored long-term at -80°C. This method is suitable for the quantitative assessment of mitochondria, rough endoplasmic reticulum (RER), and Golgi structures, as well as organelles originating from autophagy signaling. Frozen pancreatic tissue exhibited no signs of freezing- or storage-related damage and was undistinguishable from fresh material subjected to standard glutaraldehyde fixation. Since pancreatic tissue is the most delicate tissue to work with due to the high expression of digestive enzymes, our method is also suitable for other tissue types such as liver. Thus, by applying proper tissue freezing and fixation techniques, retrospective TEM analysis can be performed on mammalian tissues in a time- and cost-saving manner.

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.

Patients With Sentinel Acute Pancreatitis of Alcoholic Etiology Are at Risk for Organ Failure and Pancreatic Necrosis: A Dual-Center Experience

OBJECTIVES

To assess the relationship between alcoholic etiology, tobacco use, and severe acute pancreatitis (AP).

METHODS

Smoking and alcohol exposure were recorded upon admission in a cohort of patients with AP within the United States. Patients with first, "sentinel" attack of AP were identified for analysis.Associations between alcohol, smoking, and severe AP were validated in an independent cohort of patients from Spain.

RESULTS

US cohort (n = 222): Thirty-five percent developed organ failure (OF), 35% pancreatic necrosis (PNec), and 7% died. OF (54% vs 33%, P = 0.03), PNec (62% vs 31%, P = 0.006), intensive care unit admission (58% vs 36%, P = 0.03), and length of stay (LOS) (20 vs 8 days, P = 0.007) were greater in alcoholic when compared to other etiologies.Spanish cohort (n = 366): Similar differences in outcomes were also found with between alcoholic and nonalcoholic etiologies: OF (24% vs 8%, P = 0.001), PNec (38% vs 14%, P < 0.001), intensive care unit admission (20% vs 3%, P < 0.001), and LOS (17 vs 11 days, P = 0.04).Multivariable analysis confirmed alcoholic etiology to be independently associated with OF and PNec in both cohorts.

CONCLUSIONS

Alcoholic etiology is independently associated with OF and PNec in patients with sentinel AP and is important when evaluating risk for severe disease in AP.

NF-κB Restricts Inflammasome Activation via Elimination of Damaged Mitochondria

Nuclear factor κB (NF-κB), a key activator of inflammation, primes the NLRP3-inflammasome for activation by inducing pro-IL-1β and NLRP3 expression. NF-κB, however, also prevents excessive inflammation and restrains NLRP3-inflammasome activation through a poorly defined mechanism. We now show that NF-κB exerts its anti-inflammatory activity by inducing delayed accumulation of the autophagy receptor p62/SQSTM1. External NLRP3-activating stimuli trigger a form of mitochondrial (mt) damage that is caspase-1- and NLRP3-independent and causes release of direct NLRP3-inflammasome activators, including mtDNA and mtROS. Damaged mitochondria undergo Parkin-dependent ubiquitin conjugation and are specifically recognized by p62, which induces their mitophagic clearance. Macrophage-specific p62 ablation causes pronounced accumulation of damaged mitochondria and excessive IL-1β-dependent inflammation, enhancing macrophage death. Therefore, the "NF-κB-p62-mitophagy" pathway is a macrophage-intrinsic regulatory loop through which NF-κB restrains its own inflammation-promoting activity and orchestrates a self-limiting host response that maintains homeostasis and favors tissue repair.

An immortalized rat pancreatic stellate cell line RP-2 as a new cell model for evaluating pancreatic fibrosis, inflammation and immunity

BACKGROUND

Pancreatic stellate cells (PSCs) play a critical role in the pathogenesis of pancreatic fibrosis and have emerging functions as progenitor cells, immune cells or intermediaries in pancreatic exocrine secretion. Increasing evidence has shown that desmin as an exclusive cytoskeleton marker of PSC is only expressed in part of these cells. This study was to establish a desmin-positive PSC cell line and evaluate its actions on pancreatic fibrosis, inflammation and immunity.

METHODS

The presence of cytoskeletal proteins, integrin α5β1 or TLR4, was determined by immunocytochemistry while the production of desmin, collagen I, MMP-1, MMP-2, TIMP-2, or CD14 was evaluated by Western blotting. The levels of desmin, collagen I, IL-1 and IL-6 mRNA were determined by real-time quantitative PCR. The secretion of cytokines was detected by ELISA. Cell function was assessed using adhesion, migration, or proliferation assays.

RESULTS

A stable activated rat PSC cell line (designated as RP-2) was established by RSV promoter/enhancer-driven SV40 large T antigen expression. RP-2 cells retained typical PSC properties, exhibited a myofibroblast-like phenotype and persistently produced desmin. The cells produced collagen I protein, matrix metalloproteinases and inhibitors thereof. RP-2 cells demonstrated typical PSC functions, including proliferation, adherence, and migration, the latter two of which occurred in response to fibronectin and were mediated by integrin α5β1. TLR4 and its response genes including proinflammatory cytokines (IL-1, IL-6, TNF-alpha) and chemotactic cytokines (MCP-1, MIP-1α, Rantes) were produced by RP-2 cells and activated by LPS. LPS-induced IL-1 or IL-6 mRNA expression in this cell line was fully blocked with MyD88 inhibitor.

CONCLUSION

RP-2 cells provide a novel tool for analyzing the properties and functions of PSCs in the pathogenesis of fibrosis, inflammation and immunity in the pancreas.

Acute pancreatitis

Acute pancreatitis, an inflammatory disorder of the pancreas, is the leading cause of admission to hospital for gastrointestinal disorders in the USA and many other countries. Gallstones and alcohol misuse are long-established risk factors, but several new causes have emerged that, together with new aspects of pathophysiology, improve understanding of the disorder. As incidence (and admission rates) of acute pancreatitis increase, so does the demand for effective management. We review how to manage patients with acute pancreatitis, paying attention to diagnosis, differential diagnosis, complications, prognostic factors, treatment, and prevention of second attacks, and the possible transition from acute to chronic pancreatitis.