Stellate cell activation in alcoholic pancreatitis

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.

Krüppel-like Factor 5 Plays an Important Role in the Pathogenesis of Chronic Pancreatitis

Chronic pancreatitis results in the formation of pancreatic intraepithelial neoplasia (PanIN) and poses a risk of developing pancreatic cancer. Our previous study demonstrated that Krüppel-like factor 5 (KLF5) is necessary for forming acinar-to-ductal metaplasia (ADM) in acute pancreatitis. Here, we investigated the role of KLF5 in response to chronic injury in the pancreas. Human tissues originating from chronic pancreatitis patients showed increased levels of epithelial KLF5. An inducible genetic model combining the deletion of Klf5 and the activation of KrasG12D mutant expression in pancreatic acinar cells together with chemically induced chronic pancreatitis was used. The chronic injury resulted in increased levels of KLF5 in both control and KrasG12D mutant mice. Furthermore, it led to numerous ADM and PanIN lesions and extensive fibrosis in the KRAS mutant mice. In contrast, pancreata with Klf5 loss (with or without KrasG12D) failed to develop ADM, PanIN, or significant fibrosis. Furthermore, the deletion of Klf5 reduced the expression level of cytokines and fibrotic components such as Il1b, Il6, Tnf, Tgfb1, Timp1, and Mmp9. Notably, using ChIP-PCR, we showed that KLF5 binds directly to the promoters of Il1b, Il6, and Tgfb1 genes. In summary, the inactivation of Klf5 inhibits ADM and PanIN formation and the development of pancreatic fibrosis.

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.

Loss of miR-29a/b1 promotes inflammation and fibrosis in acute pancreatitis

MicroRNA-29 (miR-29) is a critical regulator of fibroinflammatory processes in human diseases. In this study, we found a decrease in miR-29a in experimental and human chronic pancreatitis, leading us to investigate the regulatory role of the miR-29a/b1 cluster in acute pancreatitis (AP) utilizing a conditional miR-29a/b1-KO mouse model. miR-29a/b1-sufficient (WT) and -deficient (KO) mice were administered supramaximal caerulein to induce AP and characterized at different time points, utilizing an array of IHC and biochemical analyses for AP parameters. In caerulein-induced WT mice, miR-29a remained dramatically downregulated at injury. Despite high-inflammatory milieu, fibrosis, and parenchymal disarray in the WT mice during early AP, the pancreata fully restored during recovery. miR-29a/b1-KO mice showed significantly greater inflammation, lymphocyte infiltration, macrophage polarization, and ECM deposition, continuing until late recovery with persistent parenchymal disorganization. The increased pancreatic fibrosis was accompanied by enhanced TGFβ1 coupled with persistent αSMA+ PSC activation. Additionally, these mice exhibited higher circulating IL-6 and inflammation in lung parenchyma. Together, this collection of studies indicates that depletion of miR-29a/b1 cluster impacts the fibroinflammatory mechanisms of AP, resulting in (a) aggravated pathogenesis and (b) delayed recovery from the disease, suggesting a protective role of the molecule against AP.

The Heterogeneity of the Tumor Microenvironment as Essential Determinant of Development, Progression and Therapy Response of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is commonly diagnosed at advanced stages and most anti-cancer therapies have failed to substantially improve prognosis of PDAC patients. As a result, PDAC is still one of the deadliest tumors. Tumor heterogeneity, manifesting at multiple levels, provides a conclusive explanation for divergent survival times and therapy responses of PDAC patients. Besides tumor cell heterogeneity, PDAC is characterized by a pronounced inflammatory stroma comprising various non-neoplastic cells such as myofibroblasts, endothelial cells and different leukocyte populations which enrich in the tumor microenvironment (TME) during pancreatic tumorigenesis. Thus, the stromal compartment also displays a high temporal and spatial heterogeneity accounting for diverse effects on the development, progression and therapy responses of PDAC. Adding to this heterogeneity and the impact of the TME, the microbiome of PDAC patients is considerably altered. Understanding this multi-level heterogeneity and considering it for the development of novel therapeutic concepts might finally improve the dismal situation of PDAC patients. Here, we outline the current knowledge on PDAC cell heterogeneity focusing on different stromal cell populations and outline their impact on PDAC progression and therapy resistance. Based on this information, we propose some novel concepts for treatment of PDAC patients.

3D Bioprinted cancer models: Revolutionizing personalized cancer therapy

After cardiovascular disease, cancer is the leading cause of death worldwide with devastating health and economic consequences, particularly in developing countries. Inter-patient variations in anti-cancer drug responses further limit the success of therapeutic interventions. Therefore, personalized medicines approach is key for this patient group involving molecular and genetic screening and appropriate stratification of patients to treatment regimen that they will respond to. However, the knowledge related to adequate risk stratification methods identifying patients who will respond to specific anti-cancer agents is still lacking in many cancer types. Recent advancements in three-dimensional (3D) bioprinting technology, have been extensively used to generate representative bioengineered tumor in vitro models, which recapitulate the human tumor tissues and microenvironment for high-throughput drug screening. Bioprinting process involves the precise deposition of multiple layers of different cell types in combination with biomaterials capable of generating 3D bioengineered tissues based on a computer-aided design. Bioprinted cancer models containing patient-derived cancer and stromal cells together with genetic material, extracellular matrix proteins and growth factors, represent a promising approach for personalized cancer therapy screening. Both natural and synthetic biopolymers have been utilized to support the proliferation of cells and biological material within the personalized tumor models/implants. These models can provide a physiologically pertinent cell-cell and cell-matrix interactions by mimicking the 3D heterogeneity of real tumors. Here, we reviewed the potential applications of 3D bioprinted tumor constructs as personalized in vitro models in anticancer drug screening and in the establishment of precision treatment regimens.

Cannabinoids Inhibited Pancreatic Cancer via P-21 Activated Kinase 1 Mediated Pathway

The anti-cancer effects of cannabinoids including CBD (Cannabidiol) and THC ((−)-trans-∆9-tetrahydrocannabinol) have been reported in the case of pancreatic cancer (PC). The connection of these cannabinoids to KRas oncogenes that mutate in more than 90% of PC, and their effects on PD-L1, a key target of immune checkpoint blockade, have not been thoroughly investigated. Using cell lines and mouse models of PC, the effects of CBD and THC on cancer growth, the interaction between PC cells and a stromal cell, namely pancreatic stellate cells (PSCs), and the mechanism(s) involved were determined by cell-based assays and mouse study in vivo. CBD and THC inhibited the proliferation of PC, PSC, and PSC-stimulated PC cells. They also suppressed pancreatic tumour growth in mice. Furthermore, CBD and/or THC reduced the expression of PD-L1 by either PC or PSC cells. Knockout of p-21 activated kinase 1 (PAK1, activated by KRas) in PC and PSC cells and, in mice, dramatically decreased or blocked these inhibitory effects of CBD and/or THC. These results indicated that CBD and THC exerted their inhibitions on PC and PSC via a p-21 activated kinase 1 (PAK1)-dependent pathway, suggesting that CBD and THC suppress Kras activated pathway by targeting PAK1. The inhibition by CBD and THC of PD-L1 expression will enhance the immune checkpoint blockade of PC.

Chronic pancreatitis

Chronic pancreatitis is a multifactorial, fibroinflammatory syndrome in which repetitive episodes of pancreatic inflammation lead to extensive fibrotic tissue replacement, resulting in chronic pain, exocrine and endocrine pancreatic insufficiency, reduced quality of life, and a shorter life expectancy. The incidence and prevalence of chronic pancreatitis is rising and no curative treatment is available. Using novel diagnostic algorithms, definitive chronic pancreatitis can be diagnosed by imaging criteria alone, whereas probable chronic pancreatitis requires clinical features and imaging criteria. Criteria for the diagnosis of early chronic pancreatitis are still under discussion and need prospective validation in clinical trials. Cross-sectional imaging should be used first; endoscopic ultrasound is needed only when CT or MRI are inconclusive or to plan therapeutic interventions. Management of chronic pancreatitis requires an interdisciplinary approach including primary care practitioners, gastroenterologists, surgeons, radiologists, pain specialists, and nutritional therapists. Patients with chronic pancreatitis should be seen at least once a year and re-evaluated for causal risk factors, symptom control, and complications such as malnutrition, pancreatic exocrine insufficiency, and diabetes; refer to a specialised centre if symptoms are poorly controlled or there is risk of deterioration. Scoring systems to monitor disease progression have been developed and validated internationally. Interventional treatments for pain or cholestasis should be done by specialists only, and early discussion of treatment approaches should include all medical disciplines involved in care. Throughout this Seminar, we address research needs such as staging of pancreatitis, aspects of malnutrition and pain, and cancer surveillance, to help improve the care of patients.

Stromal heterogeneity in pancreatic cancer and chronic pancreatitis

BACKGROUND/OBJECTIVES

An abundant stromal reaction is a hallmark of pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis (CP). The cells mainly responsible for the stromal reaction are activated pancreatic stellate cells (PSCs). Despite their crucial role, PSCs are not well characterized. PSCs share characteristics with the better-known hepatic stellate cells (HSCs). The aim of this study was a detailed analysis of PSCs in PDAC and CP.

METHODS

Whole-slide specimens of CP (n = 12) and PDAC (n = 10) were studied by histochemistry and immunohistochemistry. The stroma was evaluated using Movat's pentachrome stain. PSCs were tested by immunohistochemistry for PSC markers (α-SMA, CD34, desmin, NGFR, SPARC and tenascin C) and HSC markers (α-crystallin B, CD56, NGF, NT-3, synaptophysin and TrkC). Alpha-SMA, tenascin C, SPARC and NT-3 staining were verified on tissue micro arrays (TMAs) from a well-characterized cohort of 223 PDAC patients. PSCs isolated from human PDAC and CP tissue samples as well as HSCs were evaluated by immunofluorescence.

RESULTS

While the stroma of CP cases was characterized by a collagen-rich fibrosis, PDAC stroma displayed higher mucin content (p = 0.0002). PSCs showed variable expression of tested markers. In PDAC samples, staining of most markers was found around tumor complexes, while CP samples showed a greater variety of localizations. Alpha-SMA staining correlated with collagen-rich fibrosis (p = 0.012), while NT-3 staining correlated with mucin-rich stroma (p = 0.008). A peritumoral staining was confirmed for α-SMA, tenascin C, SPARC and NT-3 in the PDAC TMA cohort (n = 223). In a subgroup of patients with pancreatic head tumors and UICC 2009 IIB (n = 144), α-SMA staining intensity was a prognostic factor for overall survival at uni- and multivariate analysis (p = 0.036 and p = 0.002).

CONCLUSIONS

The close similarities between PSCs and HSCs were confirmed. Heterogeneous expression patterns of the tested markers might reflect different levels of activation or differentiation, or even multiple subpopulations of PSCs. Survival analysis suggests an impact of stromal composition on survival.

Validation of Demographics, Etiology, and Risk Factors for Chronic Pancreatitis in the USA: A Report of the North American Pancreas Study (NAPS) Group

BACKGROUND/OBJECTIVES

Our aim was to validate recent epidemiologic trends and describe the distribution of TIGAR-O risk factors in chronic pancreatitis (CP) patients.

METHODS

The NAPS-2 Continuation and Validation (NAPS2-CV) study prospectively enrolled 521 CP patients from 13 US centers from 2008 to 2012. CP was defined by definitive changes in imaging, endoscopy, or histology. Data were analyzed after stratification by demographic factors, physician-defined etiology, participating center, and TIGAR-O risk factors.

RESULTS

Demographics and physician-defined etiology in the NAPS2-CV study were similar to the original NAPS2 study. Mean age was 53 years (IQR 43, 62) with 55% males and 87% white. Overall, alcohol was the single most common etiology (46%) followed by idiopathic etiology (24%). Alcohol etiology was significantly more common in males, middle-aged (35-65 years), and non-whites. Females and elderly (≥65 years) were more likely to have idiopathic etiology, while younger patients (<35 years) to have genetic etiology. Variability in etiology was noted by participating centers (e.g., alcohol etiology ranged from 27 to 67% among centers enrolling ≥25 patients). Smoking was the most commonly identified (59%) risk factor followed by alcohol (53%), idiopathic (30%), obstructive (19%), and hyperlipidemia (13%). The presence of multiple TIGAR-O risk factors was common, with 1, 2, ≥3 risk factors observed in 27.6, 47.6, and 23.6% of the cohort, respectively.

CONCLUSION

Our data validate the current epidemiologic trends in CP. Alcohol remains the most common physician-defined etiology, while smoking was the most commonly identified TIGAR-O risk factor. Identification of multiple risk factors suggests CP to be a complex disease.

Asporin promotes pancreatic cancer cell invasion and migration by regulating the epithelial-to-mesenchymal transition (EMT) through both autocrine and paracrine mechanisms

Pancreatic cancer is histopathologically characterized by excessive desmoplasia induced by pancreatic stellate cells (PSCs). Asporin, an extracellular matrix (ECM) protein, is highly expressed in cancer-associated fibroblasts (CAFs). Asporin expression in PSCs and its roles in PSC-pancreatic cancer cell (PCC) interaction remain unclear. The present study firstly showed that Asporin is highly expressed in activated PSCs and is involved in PSC-mediated invasion and migration of PCCs. Exogenous Asporin interacted with the transmembrane receptor CD44 on PCCs to activate NF-κB/p65 and promoted the epithelial-mesenchymal transition (EMT) in PCCs. Furthermore, AKT and ERK pathways participated in Asporin/CD44-induced NF-κB/p65 activation in pancreatic cancer. Asporin had similar effects on PCCs via an autocrine mechanism. Consistent with our in vitro experiments, we showed that Asporin in peritumoral stroma of pancreatic cancer tissues was associated with poor clinical outcome. In conclusion, this is the first study to show that Asporin promotes EMT, invasion, and migration of PCCs by activating CD44-AKT/ERK-NF-κB pathway in paracrine and autocrine manners. Moreover, our results indicate that Asporin may be a prognostic marker and suggest that targeting the tumor microenvironment represents a promising therapeutic strategy in pancreatic cancer.

High alcohol intake in deceased donors has no effect on pancreas graft survival: a registry analysis

Outcomes of pancreas transplantation from donors with high alcohol consumption are poorly described. The UK Transplant Registry was used to determine whether donor alcohol intake influenced pancreas survival in simultaneous pancreas-kidney (SPK) transplants performed between 2006 and 2012 (n = 770). Recipients were stratified by donor alcohol intake: group I (n = 122)-high recent alcohol intake (>21 or >14 units of alcohol/week in males or females, respectively) or previous alcohol abuse and group II (n = 648)-low/unknown current intake and no previous alcohol abuse. Median current alcohol intake was higher in group I than group II: 36.3 vs. 10 units/week; P < 0.001. One- and five-year pancreas graft survivals were 88.5% and 73.6% in group I, and 87% and 74.9% in group II. There was no difference in unadjusted graft survival between groups I and II (P = 0.76), and no difference between group II and a subgroup of group I with a donor history of alcohol abuse and high current intake (P = 0.26), or from donors with current alcohol consumption of >50 units/week (P = 0.41). Pancreas donors with past alcohol abuse or current high intake are common, and graft outcomes appear to be acceptable. This analysis suggests that high donor alcohol intake, by itself, should not exclude consideration of pancreas transplantation.

Impact of Intratumoral Inflammation on Survival After Pancreatic Cancer Resection

OBJECTIVES

Pancreatic cancer (PaC) frequently results in death despite surgical resection. We sought to evaluate whether inflammation in the primary tumor was associated with early death after surgical resection.

METHODS

In this case-control study, we identified 21 individuals who died less than 12 months after surgery for PaC and 42 controls who survived more than 36 months after surgery. Differences in the composition of host inflammatory response between the groups were evaluated with univariate comparisons and odds ratios for early death were calculated using logistic regression modeling.

RESULTS

Cases were more likely to have a high tumor grade (90.5% vs 26.2%; P < 0.01). The odds of early death were increased in those with a high-grade tumor (unadjusted odds ratio, 26.77; 95% confidence interval, 5.35-134.07; P < 0.01). Conversely, the density (high vs low) of inflammatory cells in tumors was similar between the groups, and odds of early death were not associated with any inflammatory marker.

CONCLUSIONS

High tumor grade, but not altered density of inflammatory cells in the intratumoral compartment, is associated with increased odds of early death after PaC resection. Future studies evaluating the host response in multiple tumor compartments with advanced histologic techniques is needed to further elucidate the role of inflammation in PaC.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Role of microRNAs in Alcohol-Induced Multi-Organ Injury

Alcohol consumption and its abuse is a major health problem resulting in significant healthcare cost in the United States. Chronic alcoholism results in damage to most of the vital organs in the human body. Among the alcohol-induced injuries, alcoholic liver disease is one of the most prevalent in the United States. Remarkably, ethanol alters expression of a wide variety of microRNAs that can regulate alcohol-induced complications or dysfunctions. In this review, we will discuss the role of microRNAs in alcoholic pancreatitis, alcohol-induced liver damage, intestinal epithelial barrier dysfunction, and brain damage including altered hippocampus structure and function, and neuronal loss, alcoholic cardiomyopathy, and muscle damage. Further, we have reviewed the role of altered microRNAs in the circulation, teratogenic effects of alcohol, and during maternal or paternal alcohol consumption.

Pancreatic cancer: The microenvironment needs attention too!

The abundant stromal/desmoplastic reaction, a characteristic feature of a majority of pancreatic adenocarcinomas (PDAC), has only recently been receiving some attention regarding its possible role in the pathobiology of pancreatic cancer. It is now well established that the cells predominantly responsible for producing the collagenous stroma are pancreatic stellate cells (PSCs). In addition to extracellular matrix proteins, the stroma also exhibits cellular elements including, immune cells, endothelial cells and neural cells. Evidence is accumulating to indicate the presence of significant interactions between PSCs and cancer cells as well as between PSCs and other cell types in the stroma. The majority of research reports to date, using in vitro and in vivo approaches, suggest that these interactions facilitate local growth as well as distant metastasis of pancreatic cancer, although a recent study using animals depleted of myofibroblasts has raised some questions regarding the central role of myofibroblasts in cancer progression. Nonetheless, novel therapeutic strategies have been assessed, mainly in the pre-clinical setting, in a bid to interrupt stromal-tumour interactions and inhibit disease progression. The next important challenge is for the translation of such pre-clinical strategies to the clinical situation so as to improve the outcome of patients with pancreatic cancer.

Role of Parathyroid Hormone-Related Protein Signaling in Chronic Pancreatitis

Chronic pancreatitis (CP), a progressive inflammatory disease where acini are destroyed and replaced by fibrous tissue, increases the risk for pancreatic cancer. Risk factors include alcohol, smoking, and obesity. The effects of these risk factors are exacerbated in patients with mutations in genes that predispose to CP. The different environmental and genetic factors produce the same clinical phenotype; once CP develops, disease course is the same regardless of etiology. Critical questions still need to be answered to understand what modifies predisposition to develop CP in persons exposed to risk factors. We postulate that risk factors modulate endogenous pathways, with parathyroid hormone-related protein (PTHrP) signaling being one such pathway. In support, PTHrP levels are elevated in mice treated with alcohol, and in mouse models of cerulein- and pancreatic duct ligation-induced CP. Disrupting the Pthrp gene in acinar cells exerts protective effects (decreased edema, histological damage, amylase and cytokine release, and fibrosis) in these CP models. PTHrP levels are elevated in human CP. Currently, CP care lacks specific pharmacological interventions. Targeting PTHrP signaling may present a novel therapeutic strategy that inhibits pancreatic inflammation and fibrosis, especially since the risk of developing pancreatic cancer is strongly associated with duration of chronic inflammation.

Scanning electron microscopic analysis of pancreatic tissue in alcoholic and tropical chronic pancreatitis

INTRODUCTION

Chronic Pancreatitis (CP) is a heterogenous disease with alcoholic chronic pancreatitis (ACP) dominating in the West, and idiopathic or tropical chronic pancreatitis (TCP) in the tropics. The aim of this study is to assess the feasibility of using a scanning electron microscope (SEM) to analyze the ultra-structural changes in alcoholic and tropical subtypes of CP.

METHODS

Chronic pancreatitis tissue samples were taken from the biopsy samples of 16 patients (seven ACP and nine TCP) who underwent drainage procedures for CP. These samples were subjected to SEM analysis and findings of normal pancreas were compared with those of CP for appreciating differences in their architectural changes.

RESULTS

Normal architecture of pancreas could be observed as lobules of parenchyma, ductal system and definite loci of Islets of Langerhans (IOL). CP samples showed loss of architecture in the form of severe fibrosis and calcifications. In ACP, the fibrosis was predominantly seen towards the periphery of the gland sparing the periductal areas. These fibres were strangulating and damaging the parenchyma. Crystals were seen over these fibres. In TCP, fibrosis was moderate and uniform throughout the parenchyma. Moreover the crystals were larger and intraluminal. Total fatty replacement of parenchyma was a striking feature in TCP, seen exclusively in diabetics with gross atrophy of IOL.

CONCLUSION

SEM gives the real-life pictures of fibrosis, fatty change, ductal changes, calcifications and thus the actual extent of damage in CP better than the ordinary light microscopy.

Smoking, drinking, and pancreatitis: a population-based cohort study in Taiwan

OBJECTIVES

In Western population, smoking is a dose-dependent risk factor for pancreatitis, whereas a threshold of 5 drinks per day may exist for alcohol to increase pancreatitis risk. Given ethnic differences in tobacco and alcohol metabolism, we examined the associations between smoking, alcohol, and pancreatitis in Asians.

METHODS

A population-based cohort was assembled using participants of the National Health Interview Survey in Taiwan. Information on drinking and smoking was collected by in-person interview at baseline. Incident cases of pancreatitis were identified through data linkage with National Health Insurance claims database.

RESULTS

During 94,601 person-years of follow-up, 66 incident cases of pancreatitis occurred. Neither current nor ever smoking was associated with the incidence of pancreatitis (adjusted hazard ratio [aHR] 1.13; 95% confidence interval [CI], 0.62-2.06; and aHR, 1.14; 95% CI, 0.63-2.06, respectively). Dose-response analysis also showed no association between smoking and pancreatitis. By contrast, regular (aHR, 3.09; 95% CI, 1.51-6.30) and heavy alcohol drinking (aHR, 6.46; 95% CI, 3.07-13.60) were associated with an increased incidence of pancreatitis compared with abstinence.

CONCLUSIONS

In this Asian population-based cohort, alcohol was associated with pancreatitis in a dose-dependent way, but smoking was not associated with pancreatitis. These results support for ethnic differences in susceptibility to smoking- and alcohol-related pancreatitis.

The impact of hypoxia in pancreatic cancer invasion and metastasis

Intratumoral hypoxia is a common feature of solid tumors. Recent advances in cancer biology indicate that hypoxia is not only a consequence of unrestrained tumor growth, but also plays an active role in promoting tumor progression, malignancy, and resistance to therapy. Hypoxia signaling is mediated by the hypoxia-inducible factors (HIFs), which are not only stabilized under hypoxia, but also by activated oncogenes or inactivated tumor suppressors under normoxia. Hypoxia is a prominent feature of the tumor microenvironment of pancreatic tumors, also characterized by the presence of a fibrotic reaction that promotes, and is also modulated by, hypoxia. As the mechanisms by which hypoxia signaling impacts invasion and metastasis in pancreatic cancer are being elucidated, hypoxia is emerging as a key determinant of pancreatic cancer malignancy as well as an important target for therapy. Herein we present an overview of recent advances in the understanding of the impact that hypoxia has in pancreatic cancer invasion and metastasis.

Pancreatic cancer organotypics: High throughput, preclinical models for pharmacological agent evaluation

Pancreatic cancer carries a terrible prognosis, as the fourth most common cause of cancer death in the Western world. There is clearly a need for new therapies to treat this disease. One of the reasons no effective treatment has been developed in the past decade may in part, be explained by the diverse influences exerted by the tumour microenvironment. The tumour stroma cross-talk in pancreatic cancer can influence chemotherapy delivery and response rate. Thus, appropriate preclinical in vitro models which can bridge simple 2D in vitro cell based assays and complex in vivo models are required to understand the biology of pancreatic cancer. Here we discuss the evolution of 3D organotypic models, which recapitulare the morphological and functional features of pancreatic ductal adenocarcinoma (PDAC). Organotypic cultures are a valid high throughput preclinical in vitro model that maybe a useful tool to help establish new therapies for PDAC. A huge advantage of the organotypic model system is that any component of the model can be easily modulated in a short time-frame. This allows new therapies that can target the cancer, the stromal compartment or both to be tested in a model that mirrors the in vivo situation. A major challenge for the future is to expand the cellular composition of the organotypic model to further develop a system that mimics the PDAC environment more precisely. We discuss how this challenge is being met to increase our understanding of this terrible disease and develop novel therapies that can improve the prognosis for patients.

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.

Ethanol and its non-oxidative metabolites profoundly inhibit CFTR function in pancreatic epithelial cells which is prevented by ATP supplementation

Excessive alcohol consumption is a major cause of acute pancreatitis, but the mechanism involved is not well understood. Recent investigations suggest that pancreatic ductal epithelial cells (PDECs) help defend the pancreas from noxious agents such as alcohol. Because the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel plays a major role in PDEC physiology and mutated CFTR is often associated with pancreatitis, we tested the hypothesis that ethanol affects CFTR to impair ductal function. Electrophysiological studies on native PDECs showed that ethanol (10 and 100 mM) increased basal, but reversibly blocked, forskolin-stimulated CFTR currents. The inhibitory effect of ethanol was mimicked by its non-oxidative metabolites, palmitoleic acid ethyl ester (POAEE) and palmitoleic acid (POA), but not by the oxidative metabolite, acetaldehyde. Ethanol, POAEE and POA markedly reduced intracellular ATP (ATPi) which was linked to CFTR inhibition since the inhibitory effects were almost completely abolished if ATPi depletion was prevented. We propose that ethanol causes functional damage of CFTR through an ATPi-dependent mechanism, which compromises ductal fluid secretion and likely contributes to the pathogenesis of acute pancreatitis. We suggest that the maintenance of ATPi may represent a therapeutic option in the treatment of the disease.

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.

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.

An exploratory study of inflammatory cytokines as prognostic biomarkers in patients with ductal pancreatic adenocarcinoma

OBJECTIVES

We measured the serum concentration of a panel of inflammatory cytokines and evaluated their association with circulating proangiogenic biomarkers and with outcome in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

We collected serum samples from 36 patients with PDAC, 9 patients with chronic pancreatitis, and 22 healthy volunteers as a control. Inflammatory cytokines and proangiogenic biomarkers were measured using the multianalyte xMAP array and carcinoembryonic antigen (CEA) and carbohydrate 19-9 by immunoassay.

RESULTS

Patients with PDAC had higher circulating levels of interleukin 6 (IL-6) than those of patients with pancreatitis or healthy individuals and higher levels of IL-10 and tumor necrosis factor α (TNF-α) compared with those of healthy individuals. In patients with PDAC, circulating IL-6, TNF-α, IL-1β, and IL-10 correlated with serum concentrations of vascular endothelial growth factor and basic fibroblast growth factor; circulating IL-6, IL-1β, and TNF-α correlated with carbohydrate 19-9; and IL-8, IL-10, and TNF-α correlated with CEA levels. Circulating IL-8, TNF-α, and CEA; tumor stage; and lymph node metastases were associated with a poor outcome.

CONCLUSIONS

The results of this exploratory study indicate that inflammatory cytokines should be pursued as potential prognostic biomarkers as well as targets for therapy in larger studies in PDAC.

Therapeutic potential of perineural invasion, hypoxia and desmoplasia in pancreatic cancer

Pancreatic cancer is one of the most fatal human malignancies. Though a relatively rare malignancy, it remains one of the deadliest tumors, with an extremely high mortality rate. The prognosis of patients with pancreatic cancer remains poor; only patients with small tumors and complete resection have a chance of a complete cure. Pancreatic cancer responds poorly to conventional therapies, including chemotherapy and irradiation. Tumor-specific targeted therapy is a relatively recent addition to the arsenal of anti-cancer therapies. It is important to find novel targets to distinguish tumor cells from their normal counterparts in therapeutic approaches. In the past few decades, studies have revealed the molecular mechanisms of pancreatic tumorigenesis, growth, invasion and metastasis. The proteins that participate in the pathophysiological processes of pancreatic cancer might be potential targets for therapy. This review describes the main players in perineural invasion, hypoxia and desmoplasia and the molecular mechanisms of these pathophysiological processes.

Targeting the cancer-stroma interaction: a potential approach for pancreatic cancer treatment

Recent studies have demonstrated that the interaction between the cancer and the stroma, play a key role in the development of pancreatic cancer. The desmoplasia, which consists of fibroblasts, pancreatic stellate cells, lymphatic and vascular endothelial cells, immune cells, pathologic increased nerves, and the extracellular matrix (ECM), creates a complex tumor microenvironment that promotes pancreatic cancer development, invasion, metastasis, and resistance to chemotherapy. Thus, the potential approach for targeting the components of this desmoplastic reaction or the pancreatic tumor microenvironment might represent a novel therapeutic approach to advanced pancreatic carcinoma. Novel therapies that target on the pancreatic tumor microenvironment should become one of the more effective treatments for pancreatic cancer.

Can we expect progress in the treatment of fibrosis in the course of chronic pancreatitis?

Chronic pancreatitis (CP) is a necroinflammatory process characterized by loss of both exocrine and endocrine function. To date, the disease has been treated symptomatically. Real advances in CP management can be expected once the pathophysiology of the disease is elucidated and individual stages of its development are properly managed. A key role in the CP pathogenesis is played by activation of pancreatic stellate cells (PSCs) that cooperate with the remaining pancreatic cells. All these cells produce cytokines, growth factors, angiotensin and other substances, which paracrinally or autocrinally induce further, persistent activation of PSCs. The activated PSCs are capable of producing and modifying the extracellular matrix. An optimal therapeutic preparation should exert beneficial effects on all the above-mentioned phenomena observed in CP. The most promising treatment modalities include blocking of the renin-angiotensin system (RAS), activation of peroxisome proliferator-activated receptors gamma (PPAR-γ), influence on the remaining PSC signaling pathways, blocking of substances produced by activated PSCs, and antioxidants. The findings of many recent experimental studies are highly encouraging; however, their efficacy should be confirmed in well-designed clinical trials.

Pancreatic stellate cells promotes the perineural invasion in pancreatic cancer

Perineural invasion is a prominent characteristic of pancreatic cancer. Pancreatic cancer has an extremely high incidence of perineural invasion which has been associated with poor survival. Early studies mostly focus on the interaction between cancer cells and nerves. Recently, the effect of pancreatic stellate cells in progression of pancreatic cancer has been paid more attention. Both in vitro studies and in vivo ones revealed that pancreatic stellate cells can enhance the proliferation, migration and invasion of pancreatic cancer cells. Pancreatic stellate cells can also regulate the expression and effect of molecules involved in perineural invasion. In addition, pancreatic stellate cells seems to associated with the generation of neuronal plasticity in pancreatic cancer. Herein the hypothesis that pancreatic stellate cells play a potential role in promote the perineural invasion in pancreatic cancer through three mechanisms. One is that pancreatic stellate cells enhance the proliferation, migration and invasion directly through releasing a variety of stimuli and providing a suitable microenvironment. Pancreatic stellate cells also regulate the expression and effects of molecules involved in perineural invasion such as nerve growth factor. Another is that pancreatic stellate cells induce neuronal plasticity, which makes nerves more vulnerable to be invaded. We can conclude that pancreatic stellate cells play a central role in regulating the perineural invasion process by producing different effects on cancer cells and nerve. To inhibit the activity of pancreatic stellate cells or block the interaction between pancreatic stellate cells and cancer cells or nerve tissue might reduce the perineural invasion in pancreatic cancer.

The fibrosis of chronic pancreatitis: new insights into the role of pancreatic stellate cells

SIGNIFICANCE

Prominent fibrosis is a major histological feature of chronic pancreatitis, a progressive necroinflammatory condition of the pancreas, most commonly associated with alcohol abuse. Patients with this disease often develop exocrine and endocrine insufficiency characterized by maldigestion and diabetes. Up until just over a decade ago, there was little understanding of the pathogenesis of pancreatic fibrosis in chronic pancreatitis.

RECENT ADVANCES

In recent times, significant progress has been made in this area, mostly due to the identification, isolation, and characterization of the cells, namely pancreatic stellate cells (PSCs) that are now established as key players in pancreatic fibrogenesis. In health, PSCs maintain normal tissue architecture via regulation of the synthesis and degradation of extracellular matrix (ECM) proteins. During pancreatic injury, PSCs transform into an activated phenotype that secretes excessive amounts of the ECM proteins that comprise fibrous tissue.

CRITICAL ISSUES

This Review summarizes current knowledge and critical aspects of PSC biology which have been increasingly well characterized over the past few years, particularly with respect to the response of PSCs to factors that stimulate or inhibit their activation and the intracellular signaling pathways governing these processes. Based on this knowledge, several therapeutic strategies have been examined in experimental models of pancreatic fibrosis, demonstrating that pancreatic fibrosis is a potentially reversible condition, at least in early stages.

FUTURE DIRECTIONS

These will involve translation of the laboratory findings into effective clinical approaches to prevent/inhibit PSC activation so as to prevent, retard, or reverse the fibrotic process in pancreatitis.

Recruitment and activation of pancreatic stellate cells from the bone marrow in pancreatic cancer: a model of tumor-host interaction

Background and Aims

Chronic pancreatitis and pancreatic cancer are characterised by extensive stellate cell mediated fibrosis, and current therapeutic development includes targeting pancreatic cancer stroma and tumor-host interactions. Recent evidence has suggested that circulating bone marrow derived stem cells (BMDC) contribute to solid organs. We aimed to define the role of circulating haematopoietic cells in the normal and diseased pancreas.

Methods

Whole bone marrow was harvested from male β-actin-EGFP donor mice and transplanted into irradiated female recipient C57/BL6 mice. Chronic pancreatitis was induced with repeat injections of caerulein, while carcinogenesis was induced with an intrapancreatic injection of dimethylbenzanthracene (DMBA). Phenotype of engrafted donor-derived cells within the pancreas was assessed by immunohistochemistry, immunofluorescence and in situ hybridisation.

Results

GFP positive cells were visible in the exocrine pancreatic epithelia from 3 months post transplantation. These exhibited acinar morphology and were positive for amylase and peanut agglutinin. Mice administered caerulein developed chronic pancreatitis while DMBA mice exhibited precursor lesions and pancreatic cancer. No acinar cells were identified to be donor-derived upon cessation of cerulein treatment, however rare occurrences of bone marrow-derived acinar cells were observed during pancreatic regeneration. Increased recruitment of BMDC was observed within the desmoplastic stroma, contributing to the activated pancreatic stellate cell (PaSC) population in both diseases. Expression of stellate cell markers CELSR3, PBX1 and GFAP was observed in BMD cancer-associated PaSCs, however cancer-associated, but not pancreatitis-associated BMD PaSCs, expressed the cancer PaSC specific marker CELSR3.

Conclusions

This study demonstrates that BMDC can incorporate into the pancreas and adopt the differentiated state of the exocrine compartment. BMDC that contribute to the activated PaSC population in chronic pancreatitis and pancreatic cancer have different phenotypes, and may play important roles in these diseases. Further, bone marrow transplantation may provide a useful model for the study of tumor-host interactions in cancer and pancreatitis.

Role of matrix metalloproteinase 3 gene promoter polymorphism in chronic pancreatitis

AIM

To study the role of 5A/6A polymorphism of matrix metalloproteinase (MMP-3) and their levels in the pathogenesis of chronic pancreatitis (CP).

METHODS

One hundred and twenty CP patients and an equal number of age and sex-matched healthy controls were included in the study. Genotypes were determined for 5A/6A allele of MMP-3 gene by allele specific PCR (AS-PCR). The serum MMP-3 levels were estimated using sandwich ELISA method.

RESULTS

The distribution of the genotypes of the 5A/6A polymorphism in both control and study patients was similar (p = 0.523). Within the disease group, patients with older age, early onset of the disease, and addictions such as smoking and alcohol consumption had higher levels as compared to those who did not have these features.

CONCLUSION

We conclude that functional polymorphism of MMP-3 (5A/6A) is not associated with CP. However, the higher levels within the disease group indicate its possible role in the disease process.

Smoking is related to pancreatic fibrosis in humans

OBJECTIVES

Smokers are at risk for pancreatic cancer (PC) and other pancreatic diseases. Cigarette smoking also aggravates the risk of PC in patients with hereditary and chronic pancreatitis (CP) and results in a higher incidence of acute pancreatitis and relapses in CP. Both PC and CP are characterized by a progressive fibrosis. Recently, two studies on rats reported that tobacco smoking is associated with chronic pancreatic inflammation with fibrosis and scarring of pancreatic acinar structures. In this study, we aimed to confirm a relationship between cigarette smoking and pancreatic fibrosis (PF) in humans.

METHODS

In this retrospective study, pancreatic and liver tissue acquired during autopsy was collected and analyzed. PF was scored by assessing severity of intralobular, extralobular, and total PF: grade 0 (normal or mild; 0-25% PF), grade 1 (moderate; 25-50% PF), and grade 2 (severe; >50%). Information on smoking habits was extracted from (electronic) medical records.

RESULTS

Of 900 autopsies performed from January 2005 to December 2007, a minority of patients (n=111) met all inclusion criteria for analysis. Grade 2-3 total PF and intralobular PF was significantly more present in smokers vs. "never-smokers" (total: 42.9 vs. 26.5%, P=0.027 and intralobular: 39.3 vs. 15.6%, P=0.013), whereas no differences could be found between never-smokers and ex-smokers and between ex-smokers and smokers. When we took into account interlobular PF, no differences between all groups were observed. No relationship between PF and age (P=0.893), body mass index (P=0.707), and pancreatic lipomatosis (P=0.916) was observed.

CONCLUSIONS

To our knowledge, no study in humans had studied the effect of tobacco smoking on pancreatic tissue. We have demonstrated for the first time that current cigarette smoking is associated with total PF-specifically, intralobular PF-as compared with nonsmokers.

Genetics and alcohol: a lethal combination in pancreatic disease?

An association between alcohol consumption and pancreatic diseases has been recognized for decades, but the absolute risk for pancreatic disease for individuals who drink alcohol is low. Other than smoking, few additional environmental factors have been identified, which suggests that genetic risk factors may be important. Studies in our laboratory using the Lieber-DeCarli feeding technique demonstrate that alcohol causes oxidative stress and mitochondrial damage and alters neruohormonal regulation of the pancreas after a threshold dose is exceeded, which makes the pancreas susceptible to withdrawal hypersensitivity and acute pancreatitis. Alcohol also shifts cell death from apoptosis to necrosis and promotes fibrosis through anti-inflammatory immune mechanisms. Others have demonstrated that alcohol lowers the threshold for trypsin activation in acinar cells, which increases sensitivity to triggering pancreatitis. In addition, we used the Lieber-DeCarli diet plus recurrent acute pancreatitis insults to develop the first animal model of chronic pancreatitis that mimics human disease. Finally, our North American Pancreatitis Study 2 (NAPS2), which was built on insights from animal studies, confirmed the threshold effect predicted by Charles Lieber (>5 drinks per day and >35 drinks/week). These studies and others also defined distinctive roles of alcohol and genetics in the etiology and progression of chronic pancreatitis.

Adiponectin deficiency enhanced the severity of cerulein-induced chronic pancreatitis in mice

BACKGROUND

Adiponectin is recognized as an antiinflammatory and antifibrotic protein derived from adipocytes, and low serum adiponectin levels are present in obesity. Recent studies have highlighted the relationship between obesity and pancreatic diseases. However, the role of adiponectin in chronic pancreatitis remains uncertain. The aim of this study was to determine the effects of adiponectin in chronic pancreatitis.

METHODS

We investigated the effects of adiponectin in experimental chronic pancreatitis by using adiponectin-knockout (APN-KO) mice. Chronic pancreatitis was induced by repeated hourly (6 times) intraperitoneal injections of 50 microg/kg cerulein three times per week for 4 weeks in wild-type (WT) and APN-KO mice. We evaluated the severity of chronic pancreatitis biochemically and morphologically.

RESULTS

In cerulein-treated mice, macroscopically and histologically, severe pancreatic damage was observed in APN-KO mice compared with findings in WT mice. The histological scores for chronic pancreatitis, including glandular atrophy, pseudotubular complex, fibrosis, and total scores, were significantly higher in APN-KO mice than in WT mice. Activated pancreatic stellate cells and F4/80-positive pancreatic macrophages accumulated in the pancreas of APN-KO mice but not in WT mice. Overexpression of the mRNAs of transforming growth factor-beta1, CD68, and monocyte chemoattractant protein-1 was noted in APN-KO mice but not in WT mice. The gene expression level of collagen1 (alpha1) tended to be higher in APN-KO mice than in WT mice, albeit insignificantly.

CONCLUSIONS

Adiponectin deficiency enhanced the severity of cerulein-induced chronic pancreatitis in mice. Hypoadiponectinemia could enhance the severity of chronic pancreatitis.

The role of alcohol and smoking in pancreatitis

Chronic alcohol use has been linked to chronic pancreatitis for over a century, but it has not been until the last decade that the role of alcohol in chronic pancreatitis has been elucidated in animals and, only in recent years, in human populations. Although a dose-dependent association between alcohol consumption and chronic pancreatitis may exist, a staistical association has been shown only with the consumption of >or=5 alcoholic drinks per day. Smoking also confers a strong, independent and dose-dependent risk of pancreatitis that may be additive or multiplicative when combined with alcohol. Alcohol increases the risk of acute pancreatitis in several ways and, most importantly, changes the immune response to injury. Genetic factors are also important and further studies are needed to clarify the role of gene-environment interactions in pancreatitis. In humans, aggressive interventional counseling against alcohol use may reduce the frequency of recurrent attacks of disease and smoking cessation may help to slow the progression of acute to chronic pancreatitis.

Stimulation of stellate cells by injured acinar cells: a model of acute pancreatitis induced by alcohol and fat (VLDL)

Mechanisms leading to acute pancreatitis after a fat-enriched meal combined with excess alcohol are incompletely understood. We have studied the effects of alcohol and fat (VLDL) on pancreatic acinar cell (PAC) function, oxidative stress, and repair mechanisms by pancreatic stellate cells (PSC) leading to fibrogenesis. To do so, PAC (rat) were isolated and cultured up to 24 h. Ethanol and/or VLDL were added to PAC. We measured PAC function (amylase, lipase), injury (lactic dehydrogenase), apoptosis (TUNEL, Apo2.7, annexin V binding), oxidative stress, and lipid peroxidation (conjugated dienes, malondialdehyde, chemoluminescence); we also measured PSC proliferation (bromodeoxyuridine incorporation), matrix synthesis (immunofluorescence of collagens and fibronectin, fibronectin immunoassay), and fatty acids in PAC supernatants (gas chromatography). Within 6 h, cultured PAC degraded and hydrolyzed VLDL completely. VLDL alone (50 microg/ml) and in combination with alcohol (0.2, 0.5, and 1% vol/vol) induced PAC injury (LDL, amylase, and lipase release) within 2 h through generation of oxidative stress. Depending on the dose of VLDL and alcohol, apoptosis and/or necrosis were induced. Antioxidants (Trolox, Probucol) reduced the cytotoxic effect of alcohol and VLDL. Supernatants of alcohol/VLDL-treated PAC stimulated stellate cell proliferation and extracellular matrix synthesis. We concluded that, in the presence of lipoproteins, alcohol induces acinar cell injury. Our results provide a biochemical pathway for the clinical observation that a fat-enriched meal combined with excess alcohol consumption can induce acinar cell injury (acute pancreatitis) followed by repair mechanisms (proliferation and increased matrix synthesis in PSC).

Pancreas and liver injury are associated in individuals with increased alcohol consumption

BACKGROUND & AIMS

Although chronic pancreatitis and liver cirrhosis are common sequelae of excess alcohol consumption, the 2 conditions are rarely associated. We studied the prevalence of simultaneous liver cirrhosis and chronic pancreatitis in alcoholics.

METHODS

Postmortem autopsy data from 620 individuals with a history of excess alcohol consumption and 100 nonalcoholics (controls) were analyzed. The individuals were classified into groups based on macroscopic observations of pancreas (no injury, acute pancreatitis, fibrosis, and chronic pancreatitis) and liver (no injury, moderate steatosis, severe steatosis, and cirrhosis). The same classification system was used for histological data, which was used to confirm and correlate macroscopic results.

RESULTS

Out of the 183 patients with liver cirrhosis, 33 (18%) had chronic pancreatitis and 93 (51%) had pancreatic fibrosis. Out of the 230 patients with severe steatosis, 37 (16%) had chronic pancreatitis and 97 (42%) were found to have a pancreatic fibrosis. Thirty-three (39%) with chronic pancreatitis also showed liver cirrhosis and 37 (44%) showed severe steatosis. Thirty-eight percent of the patients with a pancreatic fibrosis were found also to have liver cirrhosis and in another 40% severe steatosis. Thirty-five patients showed neither hepatic or pancreatic injury. We found no chronic pancreatitis or liver cirrhosis in the control group (n = 100).

CONCLUSIONS

Contrary to common belief there is a close association between pancreatic and hepatic injury in patients with increased alcohol consumption, and the degree of organ damage between the 2 organs correlate.

Inflammation and pancreatic cancer: an evidence-based review

There is a growing awareness that inflammation plays a contributory role in numerous pathologies, including pancreatic carcinogenesis. Inflammatory states are characterized by the creation of reactive oxygen species and the induction of cell cycling for tissue growth and repair. The initiation, promotion and expansion of tumors may be influenced by numerous components that function in the inflammatory response. Recognized risk factors for pancreatic cancer include cigarette smoking, chronic/hereditary pancreatitis, obesity and type II diabetes. Each risk factor is linked by the fact that the inflammatory state significantly drives its pathology. This article will outline how inflammatory mechanisms are etiologically linked to pancreatic adenocarcinoma.

Mechanisms of parenchymal injury and signaling pathways in ectatic ducts of chronic pancreatitis: implications for pancreatic carcinogenesis

The pathobiology of chronic pancreatitis (CP) remains enigmatic despite remarkable progress made recently in uncovering key mechanisms involved in the initiation and progression of the disease. CP is increasingly thought of as a multifactorial disorder. Apoptosis plays a role in parenchymal destruction, the pathological hallmark of CP. The apoptotic mechanisms preferentially target the exocrine compartment, leaving endocrine islets relatively intact for a prolonged period. Exocrine cells shed their 'immunoprivileged' status, express death receptors, and are rendered susceptible to apoptosis induced by death ligands on infiltrating lymphocytes, and released locally by activated pancreatic stellate cells. Islet cells retain their 'immunoprivileged' status and activate anti-apoptotic programs through NF-kappaB. Ductal changes, including distortion, dilatation, and pancreatic ductal hypertension in the setting of CP, induce genomic damage and increased cell turnover. In addition, signaling mechanisms that play a role in the development of embryonic pancreas are reinstated, thus, playing a role in repair, regeneration, and transformation. This, in turn, leads to acino-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN). Some of these pathways are activated in pancreatic cancer. We attempt to integrate the current knowledge and major concepts in the pathogenesis of CP and to explain the mechanism of differential cell loss. We also discuss the possible implications of signaling pathway activation in pancreatic inflammation, relevant to the cellular transformation that leads to pancreatic neoplasia.

Chronic pancreatitis: report from a multicenter Italian survey (PanCroInfAISP) on 893 patients

BACKGROUND

No data on chronic pancreatitis in Italy are available yet.

AIM

To evaluate demographic, clinical, diagnostic and therapeutic aspects in patients suffering from chronic pancreatitis.

PATIENTS AND METHODS

Eligible patients were prospectively enrolled from 2000 to 2005. Information concerning demographic data, lifestyle risk factors, family and clinical history, associated factors (alcohol, autoimmunity, cystic dystrophy of the duodenal wall, obstruction, genetic mutations) concomitant diseases, diagnostic findings, and pharmacological, endoscopic and surgical therapy were gathered.

RESULTS

893 patients (74% males, mean age 53.7+/-15.2 years) were evaluated. 519/859 patients (60%) were drinkers and 555/840 (66%) were smokers. A strong positive correlation between drinking and cigarette consumption (R=0.53; p<0.0001) was found. Heavy alcohol consumption (>80g of alcohol/day for more than 5 years) was considered the most important risk factor in 300 patients (34%), obstruction in 238 (27%), alcohol and obstruction in 82 (9%), autoimmunity in 34 (4%), cystic dystrophy of the duodenal wall/groove pancreatitis in 55 (6%), gene mutations in 36 (4%), and none (idiopathic) in 148 (17%). Bile stones were diagnosed in 287 patients (33%) and cholecystectomy was performed in 329 patients (38%). Pancreatic calcifications were diagnosed in 547/879 patients (62%). Pancreatic surgery was performed in 273 patients (31%). Endoscopic sphincterotomy was performed in 371 patients (42%). Exocrine and endocrine insufficiency were found, respectively, in 373/834 (45%) and 275/885 patients (31%).

CONCLUSIONS

An unexpected low frequency of alcohol abuse and new emerging associated risk factors for chronic pancreatitis were observed in Italy.

Pancreatic stellate cells and pancreatic cancer cells: an unholy alliance

Pancreatic cancer--a tumor displaying a particularly abundant stromal reaction--is notorious for its poor prognosis. Recent studies, via newly developed orthotopic models, provide compelling evidence of an important role for pancreatic stellate cells (PSC) in pancreatic cancer progression. Characterization of the mechanisms mediating PSC-cancer interactions will lead to the development of much needed alternative therapeutic approaches to improve disease outcome.

Clinical and radiological outcome of patients suffering from chronic pancreatitis associated with gene mutations

OBJECTIVES

Cystic fibrosis transmembrane conductance regulator (CFTR), cationic trypsinogen gene (PRSS1), and serine protease inhibitor kazal type 1 (SPINK1) gene mutations have been associated with chronic pancreatitis (CP). The aim of this study was to compare clinical and radiological findings in sporadic CP with (CPgm) and without (CPwt) gene mutations.

METHODS

Data from patients observed between 2001 and 2006 were collected. All patients were tested for 25 CFTR gene mutations, for R122H and N29I on the PRSS1 gene, and for N34S mutation on the SPINK1 gene.

RESULTS

We found 34 (17.2%) of 198 patients with CPgm, 23 (11.6%) of them on the CFTR gene, 11 (5.6%) on the SPINK1, and none on the PRSS1 gene. The age at clinical onset was younger in CPgm (36.2 +/- 17.2 years) than in CPwt (44 +/- 12.6 years; P = 0.005). There were more heavy drinkers among CPwt (33%) than among CPgm (9%; P = 0.003), and the same applied to smokers (69% vs 33%, respectively; P < 0.0001). In CPgm group, the onset of pancreatic calcifications was observed more frequently in drinkers and/or smokers. Exocrine and endocrine insufficiency occurred less frequently and later in CPgm than in CPwt patients.

CONCLUSIONS

Clinical and radiological outcome differ in CPgm compared with CPwt. Alcohol, even in small quantities, and cigarette smoking influence the onset of pancreatic calcifications.

Chronic high-fat diets induce oxide injuries and fibrogenesis of pancreatic cells in rats

OBJECTIVES

The mechanism of pancreatic damages induced by chronic high-fat diets (HFDs) remains unknown. The current study was to detect the involvement of free fatty acids (FFAs) and lipid peroxidation in pancreatic injuries in rats induced by a long-term HFD.

METHODS

Rats of HFD groups (n = 12) were fed with an HFD for 2, 4, 6, 10, and 18 weeks, respectively. Pancreatic malondialdehyde content and the concentration of FFA were measured. Histopathologic changes were observed by Sirius red staining for fibrosis and immunostaining of the pancreatic stellate cells for desmin, alpha-smooth muscle actin, platelet-derived growth factor receptor type beta, and transforming growth factor beta1.

RESULTS

Pancreatic malondialdehyde content, the number of desmin and alpha-SMA positive cells significantly increased in all the HFD groups (P < 0.05). The levels of pancreatic FFA, platelet-derived growth factor receptor type beta, and transforming growth factor beta1 increased in rats of 2-, 4-, and 6-week HFD groups (P < 0.05). These enhancements were accompanied with sequential histopathology alterations that resulted from acute inflammatory response in the early stages of secondary pancreatic fibrosis.

CONCLUSIONS

The results indicate that chronic HFD increased pancreatic FFA and lipid peroxidation associated with pancreatic injuries and collagen synthesis by activated pancreatic stellate cells in rats.

Molecular mechanisms of pancreatitis: current opinion

Pancreatitis (necroinflammation of the pancreas) has both acute and chronic manifestations. Gallstones are the major cause of acute pancreatitis, whereas alcohol is associated with acute as well as chronic forms of the disease. Cases of true idiopathic pancreatitis are steadily diminishing as more genetic causes of the disease are discovered. The pathogenesis of acute pancreatitis has been extensively investigated over the past four decades; the general current consensus is that the injury is initiated within pancreatic acinar cells subsequent to premature intracellular activation of digestive enzymes. Repeated attacks of acute pancreatitis have the potential to evolve into chronic disease characterized by fibrosis and loss of pancreatic function. Our knowledge of the process of scarring has advanced considerably with the isolation and study of pancreatic stellate cells, now established as the key cells in pancreatic fibrogenesis. The present review summarizes recent developments in the field particularly with respect to the progress made in unraveling the molecular mechanisms of acute and chronic pancreatic injury secondary to gallstones, alcohol and genetic factors. It is anticipated that continued research in the area will lead to the identification and characterization of molecular pathways that may be therapeutically targeted to prevent/inhibit the initiation and progression of the disease.

Association between calcium sensing receptor gene polymorphisms and chronic pancreatitis in a US population: Role of serine protease inhibitor Kazal 1type and alcohol

AIM: To test the hypothesis that calcium sensing receptor (CASR) polymorphisms are associated with chronic pancreatitis (CP), and to determine whether serine protease inhibitor Kazal 1type (SPINK1) N34S or alcohol are necessary co-factors in its etiology.

METHODS: Initially, 115 subjects with pancreatitis and 66 controls were evaluated, of whom 57 patients and 21 controls were predetermined to carry the high-risk SPINK1 N34S polymorphism. We sequenced CASR gene exons 2, 3, 4, 5 and 7, areas containing the majority of reported polymorphisms and novel mutations. Based on the initial results, we added 223 patients and 239 controls to analyze three common nonsynonymous single nucleotide polymorphisms (SNPs) in exon 7 (A986S, R990G, and Q1011E).

RESULTS: The CASR exon 7 R990G polymorphism was significantly associated with CP (OR, 2.01; 95% CI, 1.12-3.59; P = 0.015). The association between CASR R990G and CP was stronger in subjects who reported moderate or heavy alcohol consumption (OR, 3.12; 95% CI, 1.14-9.13; P = 0.018). There was no association between the various CASR genotypes and SPINK1 N34S in pancreatitis. None of the novel CASR polymorphisms reported from Germany and India was detected.

CONCLUSION: Our United States-based study confirmed an association of CASR and CP and for the first time demonstrated that CASR R990G is a significant risk factor for CP. We also conclude that the risk of CP with CASR R990G is increased in subjects with moderate to heavy alcohol consumption.

Cannabinoids reduce markers of inflammation and fibrosis in pancreatic stellate cells

Background

While cannabinoids have been shown to ameliorate liver fibrosis, their effects in chronic pancreatitis and on pancreatic stellate cells (PSC) are unknown.

Methodology/Principal Findings

The activity of the endocannabinoid system was evaluated in human chronic pancreatitis (CP) tissues. In vitro, effects of blockade and activation of cannabinoid receptors on pancreatic stellate cells were characterized. In CP, cannabinoid receptors were detected predominantly in areas with inflammatory changes, stellate cells and nerves. Levels of endocannabinoids were decreased compared with normal pancreas. Cannabinoid-receptor-1 antagonism effectuated a small PSC phenotype and a trend toward increased invasiveness. Activation of cannabinoid receptors, however, induced de-activation of PSC and dose-dependently inhibited growth and decreased IL-6 and MCP-1 secretion as well as fibronectin, collagen1 and alphaSMA levels. De-activation of PSC was partially reversible using a combination of cannabinoid-receptor-1 and -2 antagonists. Concomitantly, cannabinoid receptor activation specifically decreased invasiveness of PSC, MMP-2 secretion and led to changes in PSC phenotype accompanied by a reduction of intracellular stress fibres.

Conclusions/Significance

Augmentation of the endocannabinoid system via exogenously administered cannabinoid receptor agonists specifically induces a functionally and metabolically quiescent pancreatic stellate cell phenotype and may thus constitute an option to treat inflammation and fibrosis in chronic pancreatitis.