Identification of potential serum exosomal microRNAs involved in acinar-ductal metaplasia that is a precursor of pancreatic cancer associated with chronic pancreatitis.

BACKGROUNDS: Due to difficulty in early diagnosis of chronic pancreatitis (CP), it is urgent to find novel biomarkers to detect CP. Exosomal microRNAs (Exo-miRNAs) located in the serum may be potential diagnostic and therapeutic targets for CP. OBJECTIVE: To identify differentially expressed Exo-miRNAs (DE-Exo-miRNAs) in the serum of CP patients, we performed a bioinformatics analysis. METHODS: The dataset GSE128508 was downloaded from the Gene Expression Omnibus (GEO) database. The analysis was carried out using BRB-ArrayTools and significance analysis of microarrays (SAM). The target genes of DE-S-Exo-miRNAs were predicted by miRWalk databases. Further gene ontology (GO) term and Kyoto Encyclopedia of Genomes (KEGG) pathway analyses were performed with plug-in ClueGO in Cytoscape software 3.7.0. Subsequently, the interaction regulatory network between encoded proteins of target genes was performed with the Search Tool for the Retrieval of Interacting Genes (STRING) database and analyzed using plug-in Molecular Complex Detection (MCODE) and cytoHubba in Cytoscape software 3.7.0. RESULTS: We identified 227 DE-Exo-miRNAs in the serum. Further analysis using the miRWalk database identified 5164 target genes of these miRNAs. The protein-protein interaction (PPI) regulatory network of 1912 potential target genes for hub 10 up-regulated miRNAs with high degrees and one down-regulated miRNAs were constructed using the STRING database and Cytoscape software. The functional analysis using Cytoscape software tool highlighted that target genes involved in pancreatic cancer. Acinar-ductal metaplasia (ADM) in the inflammatory environment of CP is a precursor of pancreatic cancer. Subsequently, we constructed a network of target genes associated with ADM and their miRNAs. CONCLUSIONS: Exo-miRNAs in the serum as well as their target genes may be promising targets for the early diagnosis and treatment of CP. In addition, we identified potential Exo-miRNAs involved in ADM that is a precursor of pancreatic cancer associated with CP.

Fraxetin prevented sodium fluoride-induced chronic pancreatitis in rats: Role of anti-inflammatory, antioxidant, antifibrotic and anti-apoptotic activities.

Chronic pancreatitis is considered a common gastrointestinal disorder, with significant morbidity and mortality. Fluoride is an important agent for the development of our body systems, especially for bone and teeth, however on its excess consumption, it deposits in different body tissues, especially the pancreas, causing its chronic inflammation and destruction. Fraxetin proved to possess versatile activities including; antioxidant, anti-inflammatory, antifibrotic, and anti-apoptotic activities. In the present study, we have evaluated the fraxetin potentiality to prevent fluoride-induced chronic pancreatitis in rats, by evaluating animal body weights and body weight gain rate, serum amylase, and lipase activities, pancreatic oxidative stress markers, cytokines, apoptotic markers, myeloperoxidase, and hydroxyproline levels, and histopathological changes. Nine-weeks-old male Wistar rats drank distilled water containing 500 ppm sodium fluoride (NaF) for 60 days to induce chronic pancreatitis. Oral fraxetin (20, 40, and 80 mg/kg/day) received simultaneously to prevent chronic pancreatitis development. Fraxetin in a dose-dependent manner alleviated chronic pancreatitis induced by NaF, as it restored the decreased body weight and weight gain rate, decreased the elevated serum amylase and lipase activities, pancreatic IL-6, TNF-α, MDA, caspase-3, MPO and hydroxyproline levels, and Bax/Bcl-2 ratio, enhanced pancreatic CAT and SOD activities, and GSH levels, besides it augmented the elevated IL-10 level, with the restoration of normal pancreatic architecture. Therefore, fraxetin could be a promising agent recommended for the prevention of fluoride-induced chronic pancreatitis in endemic areas.

Autoimmune pancreatitis - An ongoing challenge.

Autoimmune pancreatitis is a rare form of chronic pancreatitis. The first descriptions of the disease date back to the 1990s. Etiology is multifactorial, with the use of genetic, environmental and complex immunological mechanisms. It is classified into two subtypes. Type 1 is part of a group of diseases called IgG4-related disease. Clinically is autoimmune pancreatitis manifested by icterus and abdominal discomfort. It can rarely present as acute pancreatitis. There is also a completely asymptomatic form of the disease. The diagnosis is based on abnormalities in histology, imaging methods, serology, the involvement of other organs in relation to IgG4-related disease, and a significant positive response to corticosteroid therapy. Differential diagnosis between the focal form of autoimmune pancreatitis and pancreatic cancer can be complicated, with endosonography playing an important role. In the treatment, we use corticosteroids and other immunosuppressants including biological therapy. Patients with the asymptomatic disease should also be treated to prevent late complications and exocrine and endocrine insufficiency. In addition to drug treatment, endoscopic and/or surgical treatment may be necessary. Even after recovery, the disease can relapse. The relationship between autoimmune pancreatitis and malignancies has not been clearly confirmed. The goal of this review is to provide a comprehensive look at autoimmune pancreatitis and translate latest scientific knowledge into clinical practice.

Role of the Immune System and the Circadian Rhythm in the Pathogenesis of Chronic Pancreatitis: Establishing a Personalized Signature for Improving the Effect of Immunotherapies for Chronic Pancreatitis.

Pancreatitis, in both acute and chronic forms, poses a major therapeutic challenge and is associated with great morbidity and several complications. The nature of pancreatic injury in chronic pancreatitis (CP) and the wide range of causative processes that lead to CP have made effective therapy a true unmet need. Multiple physiological, genetic, environmental, and behavioral factors contribute to the development of CP. As a result, several fields of research are aimed at identifying and addressing the factors that contribute to pancreatic injury. In this article, we review the current understanding of the pathogenesis and natural history of CP. We focus on the autonomous nervous system, immune system, and role of a chronobiological therapeutic approach to alleviate symptoms and prevent or reverse pancreatic injury associated with CP. We aim to demonstrate that individualizing chronopharmacological treatments for CP is a promising direction for future treatment using immune, nervous, and circadian systems.

Chronic Inflammatory Disease in the Pancreas, Kidney and Salivary Glands of English Cocker Spaniels and Dogs of Other Breeds Shows Similar Histological Features to Human IgG4-related Disease.

Chronic pancreatitis (CP) is a common disease in the English cocker spaniel (ECS) and is characterized histologically by duct destruction, interlobular fibrosis and dense periductular and perivenous lymphocytic aggregates. These features are also found in human autoimmune pancreatitis type 1, part of a glucocorticoid-responsive, multiorgan syndrome, newly recognized as IgG4-related disease (IgG4-RD). Human IgG4-RD affects one or several organs, often showing a predominance of IgG4+ plasma cells histologically, with an IgG4+:total IgG+ plasma cell ratio of >40%. This study investigated whether ECSs with CP and/or inflammatory disease in several organs show an increase in IgG4+ plasma cells within affected tissues. Histological sections of pancreas, liver, kidney, salivary gland and conjunctiva were obtained from ECSs with idiopathic chronic inflammatory disease affecting those tissues. Tissue samples from age-matched dogs of other breeds with similar diseases were also sampled. Control diseased tissue samples, from dogs without a suspected immune-mediated disease, were included. A subset of ECSs and dogs of other breeds presented with disease in more than one organ. Immunohistochemistry was performed with primary reagents detecting total IgG and three of the four canine IgG subclasses (IgG2, IgG3 and IgG4). Normal sections of pancreas and liver showed an absence of labelled plasma cells of any subclass. Normal kidney and salivary gland sections showed the presence of a few labelled plasma cells (<10 plasma cells/high-power field). Fourteen tissue sections from 12 ECSs and seven sections from six dogs of other breeds showed elevated numbers of IgG4+ plasma cells and IgG4+:IgG+ ratios >40%. Individual dogs (ECSs and other breeds) showed marked increases in IgG4+ cells. There were no significant differences in the number of IgG4+ plasma cells between ECSs and dogs of other breeds for affected pancreas, liver, salivary glands and conjunctiva. Kidney sections had more IgG4+ cells, for both ECSs and dogs of other breeds, than did sections from other organs. Dogs of other breeds had significantly more IgG4+ plasma cells in affected kidneys than ECSs. In conclusion, several ECSs and dogs of other breeds fulfilled the histological criteria for the diagnosis of IgG4-RD, supporting the existence of a multiorgan immune-mediated disease in ECSs and some dogs of other breeds.

Hypomethylation of IL1RN and NFKB1 genes is linked to the dysbalance in IL1ß/IL-1Ra axis in female patients with type 2 diabetes mellitus.

Inflammation has received considerable attention in the pathogenesis of type 2 diabetes mellitus (T2DM). Supporting this concept, enhanced expression of interleukin (IL)-1ß and increased infiltration of macrophages are observed in pancreatic islets of patients with T2DM. Although IL-1 receptor antagonist (IL-1Ra) plays a major role in controlling of IL-1ß-mediated inflammation, its counteraction effects and epigenetic alterations in T2DM are less studied. Thus, we aimed to analyze the DNA methylation status in IL1RN, RELA (p65) and NFKB1 (p50) genes in peripheral blood mononuclear cells (PBMCs) from treated T2DM patients (n = 35) and age-/sex- matched healthy controls (n = 31). Production of IL-1ß and IL-1Ra was analyzed in plasma and supernatants from LPS-induced PBMCs. Immunomodulatory effects of IL-1ß and IL-1Ra were studied on THP-1 cells. Average DNA methylation level of IL1RN and NFKB1 gene promoters was significantly decreased in T2DM patients in comparison with healthy controls (P< 0.05), which was associated with the increased IL-1Ra (P< 0.001) and IL-1ß (P = 0.039) plasma levels in T2DM patients. Negative association between average methylation of IL1RN gene and IL-1Ra plasma levels were observed in female T2DM patients. Methylation of NFKB1 gene was negatively correlated with IL-1Ra levels in the patients and positively with IL-1ß levels in female patients. LPS-stimulated PBMCs from female patients failed to raise IL-1ß production, while the cells from healthy females increased IL-1ß production in comparison with unstimulated cells (P< 0.001). Taken together, the findings suggest that hypomethylation of IL1RN and NFKB1 gene promoters may promote the increased IL-1ß/IL-1Ra production and regulate chronic inflammation in T2DM. Further studies are necessary to elucidate the causal direction of these associations and potential role of IL-1Ra in anti-inflammatory processes in treated patients with T2DM.

Mesenchymal stromal cells and their derivatives - putative therapeutics in the management of autoimmune pancreatitis.

Autoimmune pancreatitis, a derivative of chronic pancreatitis, frequently causes acute episodes with clinical symptoms parallel to those of acute pancreatitis. Corticosteroids are effective in the treatment of 90% of autoimmune pancreatitis cases, but for the remaining 10%, options are limited. Due to their significant immunomodulatory capabilities, mesenchymal stromal cells (MSCs) have been proposed as a novel treatment strategy for various immune and inflammatory pathologies including those with autoimmune origins. Here, we not only highlight the most recent MSC live-cell experiments to address acute pancreatitis, but also discuss the opportunities afforded by the emergence of the newly identified field of MSC necrobiology. We conclude that the putative employment of MSC derivatives provides a newer and simpler therapeutic approach that could have significant advantages over the use of cells themselves.

Chronic Pancreatitis and the Development of Pancreatic Cancer.

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

Novel Autoantibody Signatures in Sera of Patients with Pancreatic Cancer, Chronic Pancreatitis and Autoimmune Pancreatitis: A Protein Microarray Profiling Approach.

Identification of disease-associated autoantibodies is of high importance. Their assessment could complement current diagnostic modalities and assist the clinical management of patients. We aimed at developing and validating high-throughput protein microarrays able to screen patients' sera to determine disease-specific autoantibody-signatures for pancreatic cancer (PDAC), chronic pancreatitis (CP), autoimmune pancreatitis and their subtypes (AIP-1 and AIP-2). In-house manufactured microarrays were used for autoantibody-profiling of IgG-enriched preoperative sera from PDAC-, CP-, AIP-1-, AIP-2-, other gastrointestinal disease (GID) patients and healthy controls. As a top-down strategy, three different fluorescence detection-based protein-microarrays were used: large with 6400, intermediate with 345, and small with 36 full-length human recombinant proteins. Large-scale analysis revealed 89 PDAC, 98 CP and 104 AIP immunogenic antigens. Narrowing the selection to 29 autoantigens using pooled sera first and individual sera afterwards allowed a discrimination of CP and AIP from PDAC. For validation, predictive models based on the identified antigens were generated which enabled discrimination between PDAC and AIP-1 or AIP-2 yielded high AUC values of 0.940 and 0.925, respectively. A new repertoire of autoantigens was identified and their assembly as a multiplex test will provide a fast and cost-effective tool for differential diagnosis of pancreatic diseases with high clinical relevance.

Multiple risk factors for diabetes mellitus in patients with chronic pancreatitis: A multicentre study of 1117 cases.

BACKGROUND: Diabetes mellitus is a common complication of chronic pancreatitis. It is traditionally considered to develop as a consequence of beta cell loss, but there might be additional factors. Recent studies have highlighted the importance of type 2 diabetes-related risk factors in this context and population-based studies show increased risk of diabetes following acute pancreatitis. The aim of this study was to explore multiple risk factors for diabetes in patients with chronic pancreatitis. METHODS: We conducted a multicentre, cross-sectional study of patients with definitive chronic pancreatitis according to the M-ANNHEIM criteria. We used multivariable logistic regression models to determine risk factors independently associated with diabetes. RESULTS: The study included 1117 patients of whom 457 (40.9 %) had diabetes. The mean age was 52.8 ± 14.2 years and 67% were men. On multivariate analysis, parameters indicative of beta cell loss (pancreatic calcification, exocrine insufficiency, pancreatic resection) were confirmed as independent risk factors for diabetes (all p ≤ 0.02). In addition, type 2 diabetes-related risk factors (dyslipidaemia and overweight/obesity) were associated with the presence of diabetes (all p ≤ 0.002). Patients with a history of pancreatic fluid collections (indicative of previous attacks of acute pancreatitis) had a marginally increased risk of diabetes (p = 0.07). CONCLUSION: In patients with chronic pancreatitis the presence of diabetes is associated with multiple risk factors including type 2 diabetes-related factors. Our observations attest to the understanding of this entity and may have implications for treatment.

Distinct immune characteristics distinguish hereditary and idiopathic chronic pancreatitis.

Chronic pancreatitis (CP) is considered an irreversible fibroinflammatory pancreatic disease. Despite numerous animal model studies, questions remain about local immune characteristics in human CP. We profiled pancreatic immune cell characteristics in control organ donors and CP patients including those with hereditary and idiopathic CP undergoing total pancreatectomy with islet autotransplantation. Flow cytometric analysis revealed a significant increase in the frequency of CD68+ macrophages in idiopathic CP. In contrast, hereditary CP samples showed a significant increase in CD3+ T cell frequency, which prompted us to investigate the T cell receptor ß (TCRß) repertoire in the CP and control groups. TCRß sequencing revealed a significant increase in TCRß repertoire diversity and reduced clonality in both CP groups versus controls. Interestingly, we observed differences in Vß-Jß gene family usage between hereditary and idiopathic CP and a positive correlation of TCRß rearrangements with disease severity scores. Immunophenotyping analyses in hereditary and idiopathic CP pancreases indicate differences in innate and adaptive immune responses, which highlights differences in immunopathogenic mechanisms of disease among subtypes of CP. TCR repertoire analysis further suggests a role for specific T cell responses in hereditary versus idiopathic CP pathogenesis, providing insights into immune responses associated with human CP.

Piperine ameliorates the severity of fibrosis via inhibition of TGF­ß/SMAD signaling in a mouse model of chronic pancreatitis.

Chronic pancreatitis (CP) is characterized by recurrent pancreatic injury, resulting in inflammation and fibrosis. Currently, there are no drugs for the treatment of pancreatic fibrosis associated with CP. Piperine, a natural alkaloid found in black pepper, has been reported to show anti­inflammatory, anti­oxidative, and antitumor activities. Although piperine exhibits numerous properties in regards to the regulation of diverse diseases, the effects of piperine on CP have not been established. To investigate the effects of piperine on CP in vivo, we induced CP in mice through the repetitive administration of cerulein (50 µg/kg) six times at 1­h intervals, 5 times per week, for a total of 3 weeks. In the pre­treatment groups, piperine (1, 5, or 10 mg/kg) or corn oil were administrated orally at 1 h before the first cerulein injection, once a day, 5 times a week, for a total of 3 weeks. In the post­treatment groups, piperine (10 mg/kg) or corn oil was administered orally at 1 or 2 week after the first cerulein injection. Pancreases were collected for histological analysis. In addition, pancreatic stellate cells (PSCs) were isolated to examine the anti­fibrogenic effects and regulatory mechanisms of piperine. Piperine treatment significantly inhibited histological damage in the pancreas, increased the pancreatic acinar cell survival, reduced collagen deposition and reduced pro­inflammatory cytokines and chemokines. In addition, piperine treatment reduced the expression of fibrotic mediators, such as α­smooth muscle actin (α­SMA), collagen, and fibronectin 1 in the pancreas and PSCs. Moreover, piperine treatment reduced the production of transforming growth factor (TGF)­ß in the pancreas and PSCs. Furthermore, piperine treatment inhibited TGF­ß­induced pSMAD2/3 activation but not pSMAD1/5 in the PSCs. These findings suggest that piperine treatment ameliorates pancreatic fibrosis by inhibiting TGF­ß/SMAD2/3 signaling during CP.

Systemic inflammation contributes to impairment of quality of life in chronic pancreatitis.

Chronic pancreatitis (CP) is a fibrotic disorder of the pancreas leading to clinical sequelae like pain and an excess of comorbidity including cardiovascular disease and cancers. The aim of this study was to determine the relationship between systemic inflammation and quality of life in patients with CP. Patients were prospectively recruited and underwent a quality of life assessment (EORTC QLQ-C30 and PAN 28). The serum inflammatory profile was assessed using an MSD 30-plex array. The relationship between clinical variables, inflammatory cytokines and quality of life was determined by a GLM-MANOVA and the individual impact of significant variables evaluated by a second ANOVA. In total, 211 patients with a median age of 53 years were recruited across 5 European centres. Gender, age, nicotine and alcohol abuse were clinical variables associated with altered quality of life. Systemic inflammation with high levels of pro-inflammatory cytokines (Eotaxin, IL-1ß, IL-7, IL-8, IL-12/IL-23p40, IL-12p70, IL-13, IL-16, IP-10, MCP-1, MCP-4, MDC, MIP-1a, TARC, TNFß) was associated with diminished quality of life in general and specific domains including pain, physical and cognitive functioning. As conclusion, CP is associated with a systemic inflammatory response that has a negative impact on quality of life and accelerates aging.

Autoantibody detection is not recommended for chronic pancreatitis: a cross-sectional Study of 557 patients.

BACKGROUND: Autoimmune factor was regarded as one of the risk factors in the pathogenesis of chronic pancreatitis (CP), especially for autoimmune pancreatitis (AIP). However, whether autoimmune factor plays a role in non-AIP CP or not was unknown. METHODS: Hospitalized patients with non-AIP CP from January 2010 to October 2016 were detected for 22 autoantibodies at the time of hospital admission. Autoantibodies with frequency > 0.5% were enrolled to calculate the frequency in historial healthy controls through literature search in PubMed. Differentially expressed autoantibodies were determined between patients and historial healthy controls, and related factors were identified by multivariate logistic regression analysis. RESULTS: In a total of 557 patients, 113 cases were detected with 19 kinds of positive autoantibodies, among them anti-ß2-glycoprotein I (ß2-GPI) antibody was most frequent (9.16%). Compared with historial healthy controls, the frequencies of serum ß2-GPI and anti SS-B antibody in patients were significantly higher, while frequencies of anti-smooth muscle antibody and anticardiolipin antibody were significantly lower (all P < 0.05). Multivariate logistic regression analysis result showed that diabetes mellitus (OR = 2.515) and common bile duct stricture (OR = 2.844) were the risk factors of positive ß2-GPI antibody in patients while diabetes mellitus in first-/second-/third-degree relatives (OR = 0.266) was the protective factor. There were no related factors for other three differentially expressed autoantibodies. CONCLUSIONS: Four autoantibodies were expressed differentially between patients with non-AIP CP and historial healthy controls. Due to limited significance for diagnosis and treatment of chronic pancreatitis, autoantibodies detection is not recommended conventionally unless suspected of AIP.

The prognostic significance of glutamic acid decarboxylase antibodies in patients with chronic pancreatitis undergoing total pancreatectomy with islet autotransplantation.

AIM: Islet autotransplantation (IAT) is considered a 'non-immune' model of islet transplant, with no risk for autoimmune-mediated beta cell loss, but we have previously observed de novo type 1 diabetes in one total pancreatectomy with islet autotransplantation (TPIAT) recipient. We aimed to investigate the clinical significance of glutamic acid decarboxylase antibodies (GADA), as a sensitive marker for autoimmune diabetes mellitus (DM), in patients with chronic pancreatitis undergoing TPIAT. METHODS: We identified 9 patients undergoing TPIAT with elevated GADA pre-TPIAT (8 non-diabetic and 1 with C-peptide positive DM), otherwise demographically similar to GADA negative TPIAT recipients (n=341). Metabolic and clinical measures related to islet cell function were recorded both before and after TPIAT. RESULTS: None of the 9 TPIAT patients achieved insulin independence after surgery, vs. 33% of GADA negative patients (n=318 with 1-yr follow-up). The two patients with the highest titters of GADA (>250 IU/mL) both experienced islet graft failure, despite normoglycaemia pre-TPIAT and high islet mass transplanted (5276 and 9378 IEQ per kg), with elevated HbA1c levels post-TPIAT (8.3%, 9.6%). The remaining 7 seven were insulin dependent with partial graft function and HbA1c levels <7%. CONCLUSION: Insulin dependence was more frequent in 9 patients with elevated GADA prior to TPIAT than in GADA negative TPIAT recipients, with graft failure in 2 cases. We speculate that beta-cell autoimmunity may occur in a small subset of TPIAT recipients and that beta cell antibody testing prior to TPIAT may be warranted to identify individuals at higher risk for insulin dependence.

Tumefactive Inflammatory Diseases of the Pancreas.

Advances in the past two decades have resulted in the recognition of several tumefactive pancreatic lesions that, on histologic evaluation, show a varying combination of inflammation and fibrosis. Autoimmune pancreatitis, the prototypic tumefactive pancreatic fibroinflammatory lesion, is composed of two distinct diseases, type 1 autoimmune pancreatitis and the less common type 2 autoimmune pancreatitis. Although designated as autoimmune pancreatitis, the two diseases show little morphologic or pathogenic overlap. In type 1 disease, subsets of T lymphocytes (type 2 helper T cells, regulatory T cells, and T follicular helper 2 cells) are hypothesized to drive the inflammatory reaction. The B-cell response is characterized by an oligoclonal expansion of plasmablasts, with dominant clones that vary among patients and distinct clones that emerge at the time of relapse. Although the precise role of IgG4 in this condition remains uncertain, recent studies suggest that other IgG subclasses (eg, IgG1) may mediate the immune reactions, whereas IgG4 represents a response to dampen excessive inflammation. A recent study of type 2 autoimmune pancreatitis highlights the role of CXCL8 (alias IL-8), with duct epithelium and infiltrating T lymphocytes expressing this chemokine; the latter may contribute to the distinct form of neutrophilic inflammation in this disease. The review also highlights other forms of mass-forming chronic pancreatitis: follicular pancreatitis, groove pancreatitis, and those associated with rheumatologic diseases.

Unique properties of IgG4 antibody and its clinical application in autoimmune pancreatitis.

BACKGROUND: Autoimmune pancreatitis (AIP) is defined as a unique form of chronic pancreatitis characterized by clinical presentation with obstructive jaundice, a dense lymphoplasmacytic infiltrate and fibrosis histologically, and a dramatic response to steroids therapeutically. The possible role of IgG4 in driving the pathology of AIP is a controversial subject that has not been addressed satisfactorily.  Objective: The purpose of this review is to discuss the unique biology of IgG4 that are important for its role and the clinical applications for serologic detection. METHODS: Review of current literature about IgG4 antibody in the clinical application in AIP. RESULTS: High serum levels of IgG4 are an important biomarker and broadly used for diagnosis, differentiation from diseases especially pancreatic cancer, and as a parameter to indicate disease activity, extra-pancreatic lesions, and treatment monitoring. However, some controversial studies show it has a limited specificity and sensitivity in these conditions.  Conclusion: Although increasing studies have promoted our understanding of the structure and function of IgG4, there is still dilemma between the beneficial and the adverse aspect of IgG4 in the pathogenesis of AIP.

Immune Cell Production of Interleukin 17 Induces Stem Cell Features of Pancreatic Intraepithelial Neoplasia Cells.

BACKGROUND & AIMS: Little is known about how the immune system affects stem cell features of pancreatic cancer cells. Immune cells that produce interleukin 17A (IL17A) in the chronically inflamed pancreas (chronic pancreatitis) contribute to pancreatic interepithelial neoplasia (PanIN) initiation and progression. We investigated the effects that IL17A signaling exerts on pancreatic cancer progenitor cells and the clinical relevance of this phenomena. METHODS: We performed studies with Mist1Cre;LSLKras;Rosa26mTmG (KCiMist;G) and Kras(G12D);Trp53(R172H);Pdx1-Cre (KPC) mice (which upon tamoxifen induction spontaneously develop PanINs) and control littermates. Some mice were injected with neutralizing antibodies against IL17A or control antibody. Pancreata were collected, PanIN epithelial cells were isolated by flow cytometry based on lineage tracing, and gene expression profiles were compared. We collected cells from pancreatic tumors of KPC mice, incubated them with IL17 or control media, measured expression of genes regulated by IL17 signaling, injected the cancer cells into immune competent mice, and measured tumor growth. IL17A was overexpressed in pancreata of KCiMist mice from an adenoviral vector. Pancreata were collected from all mice and analyzed by histology and immunohistochemistry. Levels of DCLK1 and other proteins were knocked down in KPC pancreatic cancer cells using small interfering or short hairpin RNAs; cells were analyzed by immunoblotting. We obtained 65 pancreatic tumor specimens from patients, analyzed protein levels by immunohistochemistry, and compared results with patient survival times. We also analyzed gene expression levels and patient outcome using The Cancer Genome Atlas database. RESULTS: PanIN cells from KCiMist;G mice had a gene expression pattern associated with embryonic stem cells. Mice given injections of IL17-neutralizing antibodies, or with immune cells that did not secrete IL17, lost this expression pattern and had significantly decreased expression of DCLK1 and POU2F3, which regulate tuft cell development. KCiMist mice that overexpressed IL17 formed more PanINs, with more DCLK1-positive cells, than control mice. Pancreatic tumor cells from KPC mice and human Capan-2 cells exposed to IL17A had increased activation of NF-κB and mitogen-activated protein kinase signaling and increased expression of DCLK1 and ALDH1A1 (a marker of embryonic stem cells) compared with cells in control media. These cells also formed tumors faster that cells not exposed to IL17 when they were injected into immunocompetent mice. KPC cells with knockdown of DCLK1 expressed lower levels of ALDH1A1 after incubation with IL17 than cells without knockdown. Expression of the IL17 receptor C was higher in DCLK1-positive PanIN cells from mice compared with DCLK1-negative PanIN cells. In human pancreatic tumor tissues, high levels of DCLK1 associated with a shorter median survival time of patients (17.7 months, compared with 26.6 months of patients whose tumors had low levels of DCLK1). Tumor levels of POU2F3 and LAMC2 were also associated with patient survival time. CONCLUSIONS: In studies of mouse and human pancreatic tumors and precursors, we found that immune cell-derived IL17 regulated development of tuft cells and stem cell features of pancreatic cancer cells via increased expression of DCLK1, POU2F3, ALDH1A1, and IL17RC. Strategies to disrupt this pathway might be developed to prevent pancreatic tumor growth and progression.