Changes in pancreatic exocrine function in young at-risk children followed to islet autoimmunity and type 1 diabetes in the ENDIA study.

BACKGROUNDS: We aimed to monitor pancreatic exocrine function longitudinally in relation to the development of islet autoimmunity (IA) and type 1 diabetes (T1D) in at-risk children with a first-degree relative with T1D, who were followed prospectively in the Environmental Determinants of Islet Autoimmunity (ENDIA) study. METHODS: Fecal elastase-1 (FE-1) concentration was measured longitudinally in 85 ENDIA children from median age 1.0 (IQR 0.7,1.3) year. Twenty-eight of 85 children (progressors) developed persistent islet autoantibodies at median age of 1.5 (IQR 1.1,2.5) years, of whom 11 went on to develop clinical diabetes. The other 57 islet autoantibody-negative children (non-progressors) followed similarly were age and gender-matched with the progressors. An adjusted linear mixed model compared FE-1 concentrations in progressors and non-progressors. RESULTS: Baseline FE-1 did not differ between progressors and non-progressors, or by HLA DR type or proband status. FE-1 decreased over time in progressors in comparison to non-progressors (Wald statistic 5.46, P = .02); in some progressors the fall in FE-1 preceded the onset of IA. CONCLUSIONS: Pancreatic exocrine function decreases in the majority of young at-risk children who progress to IA and T1D.

Men1 maintains exocrine pancreas homeostasis in response to inflammation and oncogenic stress.

A more comprehensive understanding of the molecular mechanisms underlying pancreatic diseases, including pancreatitis and cancer, is essential to improve clinical management. MEN1 has established roles in epigenetic regulation and tumor suppression in the endocrine pancreas; however, intriguing recent data suggest MEN1 may also function in the exocrine pancreas. Using physiologically relevant genetic mouse models, we provide direct evidence that Men1 is essential for exocrine pancreas homeostasis in response to inflammation and oncogenic stress. Men1 loss causes increased injury and impaired regeneration following acute caerulein-induced pancreatitis, leading to more severe damage, loss of the normal acinar compartment, and increased cytokeratin 19-positive metaplasias and immune cell infiltration. We further demonstrate the Men1 protein is stabilized in response to insult, and loss of Men1 is associated with the overexpression of proinflammatory Jund target genes, suggesting that loss of Men1-mediated repression of Jund activity is, at least in part, responsible for the impaired response. Finally, we demonstrate that Men1 loss significantly accelerates mutant Kras-dependent oncogenesis. Combined, this work establishes Men1 as an important mediator of pancreas homeostasis in vivo.

New Evidence of Exocrine Pancreatopathy in Pre-symptomatic and Symptomatic Type 1 Diabetes.

PURPOSE OF REVIEW: Type 1 diabetes (T1D) is one of the most frequent chronic autoimmune diseases in humans, characterized by the lack of insulin production resulting in high blood glucose levels and lifelong requirement of exogenous insulin administration for survival. It is now recognized that the autoimmune process begins years before the clinical onset, in a stage called pre-symptomatic T1D, in which the presence of ß-cell-specific autoantibodies is detectable. Our aim is to review evidence for T1D as a "whole-pancreas disease," featured by both endocrine and exocrine pancreas alterations already at early disease stages. RECENT FINDINGS: In this review, we discuss a series of recent observations indicating that in genetically predisposed individuals, structural and functional abnormalities as well as immune cell infiltration of the exocrine pancreas are already present in the pre-symptomatic stages of the disease. Despite T1D being considered a ß-cell-specific disease, numerous reports point to the presence of exocrine pancreas subclinical abnormalities occurring during disease development. These observations challenge the long-standing idea that T1D exocrine damage exists as a mere consequence of disease progression and provide further explanation of mechanisms underlying T1D pathogenesis.

Echovirus 6 Infects Human Exocrine and Endocrine Pancreatic Cells and Induces Pro-Inflammatory Innate Immune Response.

Human enteroviruses (HEV), especially coxsackievirus serotype B (CVB) and echovirus (E), have been associated with diseases of both the exocrine and endocrine pancreas, but so far evidence on HEV infection in human pancreas has been reported only in islets and ductal cells. This study aimed to investigate the capability of echovirus strains to infect human exocrine and endocrine pancreatic cells. Infection of explanted human islets and exocrine cells with seven field strains of E6 caused cytopathic effect, virus titer increase and production of HEV protein VP1 in both cell types. Virus particles were found in islets and acinar cells infected with E6. No cytopathic effect or infectious progeny production was observed in exocrine cells exposed to the beta cell-tropic strains of E16 and E30. Endocrine cells responded to E6, E16 and E30 by upregulating the transcription of interferon-induced with helicase C domain 1 (IF1H1), 2'-5'-oligoadenylate synthetase 1 (OAS1), interferon-ß (IFN-ß), chemokine (C-X-C motif) ligand 10 (CXCL10) and chemokine (C-C motif) ligand 5 (CCL5). Echovirus 6, but not E16 or E30, led to increased transcription of these genes in exocrine cells. These data demonstrate for the first time that human exocrine cells represent a target for E6 infection and suggest that certain HEV serotypes can replicate in human pancreatic exocrine cells, while the pancreatic endocrine cells are permissive to a wider range of HEV.

Cross-talk between TLR4 and PPARγ pathways in the arachidonic acid-induced inflammatory response in pancreatic acini.

Arachidonic acid (AA) is generally associated with inflammation in different settings. We assess the molecular mechanisms involved in the inflammatory response exerted by AA on pancreatic acini as an approach to acute pancreatitis (AP). Celecoxib (COX-2 inhibitor), TAK-242 (TLR4 inhibitor) and 15d-PGJ2 (PPARγ agonist) were used to ascertain the signaling pathways. In addition, we examine the effects of TAK-242 and 15d-PGJ2 on AP induced in rats by bile-pancreatic duct obstruction (BPDO). To carry out in vitro studies, acini were isolated from pancreas of control rats. Generation of PGE2 and TXB2, activation of pro-inflammatory pathways (MAPKs, NF-κB, and JAK/STAT3) and overexpression of CCL2 and P-selectin was found in AA-treated acini. In addition, AA up-regulated TLR4 and down-regulated PPARγ expression. Celecoxib prevented the up-regulation of CCL2 and P-selectin but did not show any effect on the AA-mediated changes in TLR4 and PPARγ expression. TAK-242, reduced the generation of AA metabolites and repressed both the cascade of pro-inflammatory events which led to CCL2 and P-selectin overexpression as well as the AA-induced PPARγ down-regulation. Thus, TLR4 acts as upstream activating pro-inflammatory and inhibiting anti-inflammatory pathways. 15d-PGJ2 down-regulated TLR4 expression and hence prevented the synthesis of AA metabolites and the inflammatory response mediated by them. Reciprocal negative cross-talk between TLR4 and PPARγ pathways is evidenced. In vivo experiments showed that TAK-242 and 15d-PGJ2 treatments reduced the inflammatory response in BPDO-induced AP. We conclude that through TLR4-dependent mechanisms, AA up-regulated CCL2 and P-selectin in pancreatic acini, partly mediated by the generation of PGE2 and TXB2, which activated pro-inflammatory pathways, but also directly by down-regulating PPARγ expression with anti-inflammatory activity. In vitro and in vivo studies support the role of TLR4 in AP and the use of TLR4 inhibitors and PPARγ agonists in AP treatment.

Hydroalcohol extract of Trigonella foenum-graecum seed attenuates markers of inflammation and oxidative stress while improving exocrine function in diabetic rats.

CONTEXT AND OBJECTIVE: The herb fenugreek, Trigonella foenum-graecum Linn (Fabaceae), seeds have been traditionally used in the treatment of diabetes but its effect on oxidative stress and pro-inflammatory cytokines in the improvement of exocrine function of diabetes has not been studied. The effect of hydroalcoholic extract of Trigonella foenum-graecum seeds (HEF) on alloxan-induced type-II diabetic rat model was investigated. MATERIALS AND METHODS: Effect of HEF (500, 1000, and 2000 mg/kg), glimepiride (4 mg/kg), and combination of HEF (500 mg/kg) + glimepiride (2 mg/kg), on alloxan-induced diabetic rats was evaluated by assaying (blood glucose, serum protein, glycosylated hemoglobin, muscle and liver glycogen, glucose uptake by diaphragm, liver glucose transport, serum pancreatic enzymes (α-amylase, lipase), pro-inflammatory cytokines (TNF-α, IL-6), antioxidant enzymes [glutathione (GSH), superoxide dismutase (SOD)], lipid peroxides (liver and pancreas), and histoarchitecture (liver, pancreas). RESULTS: Treatment with HEF (at different doses), glimepiride, and HEF + glimepiride increased body weight and glucose uptake, reduced plasma glucose, glycosylated hemoglobin, liver glucose transport, pro-inflammatory cytokines, pancreatic enzymes and restored depleted glycogen (muscle, liver) and total protein significantly (p < 0.01) and dose dependently, including prevention of lipid peroxidation and restoration of GSH and SOD (liver and pancreas). Treatment with HEF + glimepiride potentiated hypoglycemic activity of glimepiride. Histoarchitecture of liver and pancreas showed marked improvement. CONCLUSION: Present experimental findings suggest that HEF possesses promising hypoglycemic activity, presumably by amelioration of oxidative stress and pro-inflammatory cytokines. HEF may be useful as an adjuvant with clinically effective antidiabetic drugs in the management of type-II diabetes.

Increased immune cell infiltration of the exocrine pancreas: a possible contribution to the pathogenesis of type 1 diabetes.

Type 1 diabetes (T1D) results from a complex interplay between genetic susceptibility and environmental factors that have been implicated in the pathogenesis of disease both as triggers and potentiators of ß-cell destruction. CD8 T cells are the main cell type found in human islets, and they have been shown in vitro to be capable of killing ß-cells overexpressing MHC class I. In this study, we report that CD8 T cells infiltrate the exocrine pancreas of diabetic subjects in high numbers and not only endocrine areas. T1D subjects present significantly higher CD8 T cell density in the exocrine tissue without the presence of prominent insulitis. Even T1D donors without remaining insulin-containing islets and long disease duration show elevated levels of CD8 T cells in the exocrine compartment. In addition, higher numbers of CD4(+) and CD11c(+) cells were found in the exocrine tissue. Preliminary data in type 2 diabetic (T2D) subjects indicate that overall, there might be a spontaneous inflammatory infiltration of the exocrine tissue, common to both T1D and T2D subjects. Our study provides the first information on the precise tissue distribution of CD8 T cells in pancreata from T1D, T2D, autoantibody-positive, and healthy control subjects.

Regulation of pancreatic inflammation by connective tissue growth factor (CTGF/CCN2).

Pancreatitis is caused by long-term heavy alcohol consumption, which results in injury and death of pancreatic acinar cells (PAC). The PAC play a pivotal role in mediating early inflammatory responses but the underlying mechanisms remain poorly understood. Treatment of C57BL/6 mice with ethanol and cerulein resulted in increased staining for acinar interleukin- 1b (IL-1b), chemokine (C-C motif) ligand 3 (CCL3), or connective tissue growth factor (CTGF/CCN2) by Day 16 and this was associated with increased infiltration of F4/80-positive macrophages and increased expression of pancreatic CTGF/CCN2 mRNA. Compared with wild-type Swiss Webster mice, ethanol treatment of pan-green fluorescent protein (GFP)-CTGF/CCN2 transgenic mice caused enhanced acinar staining for GFP or CTGF/CCN2 and a significant increase in pancreatic infiltration of F4/80-positive macrophages or NIMP-R14-positive neutrophils. Treatment of primary mouse PAC or the rat AR42J PAC line with ethanol or CTGF/CCN2 resulted in enhanced expression of IL-1b or CCL3. Conditioned medium from CTGF/CCN2-treated AR42J cells induced chemotaxis in NR8383 macrophages and this response was abrogated in a dose dependent manner by addition of BX471, an inhibitor of chemokine (C-C motif) receptor 1. These results reveal that acinar CTGF/CCN2 plays a novel role in alcohol-induced inflammatory processes in the pancreas by increasing infiltration of macrophages and neutrophils and increasing acinar production of inflammatory mediators such as IL-1b or CCL3. The early production of CTGF/CCN2 by PAC to drive inflammation is distinct from its previously reported production by pancreatic stellate cells to drive fibrosis at later stages of pancreatic injury.

Knockdown of GRP78 promotes apoptosis in pancreatic acinar cells and attenuates the severity of cerulein and LPS induced pancreatic inflammation.

Acute pancreatitis (AP) is a potentially lethal disease characterized by inflammation and parenchymal cell death; also, the severity of AP correlates directly with necrosis and inversely with apoptosis. However, mechanisms of regulating cell death in AP remain unclear. The endoplasmic reticulum (ER) chaperone protein GRP78 has anti-apoptotic properties, in addition to modulating ER stress responses. This study used RNA interference (RNAi) approach to investigate the potential role of GRP78 in regulating apoptosis during AP. In vitro models of AP were successfully developed by treating AR42J cells with cerulein or cerulein plus lipoplysaccharide (LPS). There was more pancreatic inflammation and less apoptosis with the cerulein plus LPS treatment. Furthermore, knockdown of GRP78 expression markedly promoted apoptosis and reduced necrosis in pancreatic acinar cells. This was accomplished by enhancing the activation of caspases and inhibiting the activity of X-linked inhibitor of apoptosis protein (XIAP), as well as a receptor interacting protein kinase-1(RIPK1), which is a key mediator of necrosis. This attenuated the severity of pancreatic inflammation, especially after cerulein plus LPS treatment. In conclusion, these findings indicate that GRP78 plays an anti-apoptotic role in regulating the cell death response during AP. Therefore, GRP78 is a potential therapeutic target for AP.

Revisiting the notion of type 1 diabetes being a T-cell-mediated autoimmune disease.

PURPOSE OF REVIEW: Type 1 diabetes (T1D) research is at present in a critical period of development and during the past few years several large phase III studies targeting T-cell autoimmunity in recent-onset patients with T1D failed to reach the primary endpoint. RECENT FINDINGS: Cause and pathogenesis of T1D remain largely unknown. In humans, insulitis is discrete, affects few islets and is present only in about one-third of patients with recent-onset T1D. The rapid increase in incidence of T1D argues against a decisive role for genetic factors and instead for the hypothesis that infectious agents, possibly entering the pancreas via the ductal compartment, are involved in disease pathogenesis. Repeated episodes of bacteria or virus-induced innate inflammations affecting only certain lobes of the pancreas fit well with the reported heterogeneity of the disease within the pancreas as well as with the slow progression over many years. SUMMARY: In humans there is limited support for T1D being primarily an autoimmune disease; instead available findings support the view that T1D can be regarded as an innate inflammatory disease affecting the entire pancreas, but with its main clinical manifestations emanating from the loss of the insulin-producing cells.

Immunogenicity and cross protective ability of the central VP2 amino acids of infectious pancreatic necrosis virus in Atlantic salmon (Salmo salar L.).

Infectious pancreatic necrosis virus (IPNV) is a member of the family Birnaviridae that has been linked to high mortalities in juvenile salmonids and postsmolt stages of Atlantic salmon (Salmo salar L.) after transfer to seawater. IPN vaccines have been available for a long time but their efficacy has been variable. The reason for the varying immune response to these vaccines has not well defined and studies on the importance of using vaccine trains homologous to the virulent field strain has not been conclusive. In this study we prepared one vaccine identical to the virulent Norwegian Sp strain NVI-015 (NCBI: 379740) (T(217)A(221)T(247) of VP2) and three other vaccine strains developed using the same genomic backbone altered by reverse genetics at three residues yielding variants, T(217)T(221)T(247), P(217)A(221)A(247), P(217)T(221)A(247). These 4 strains, differing in these three positions only, were used as inactivated, oil-adjuvanted vaccines while two strains, T(217)A(221)T(247) and P(217)T(221)A(247), were used as live vaccines. The results show that these three residues of the VP2 capsid play a key role for immunogenicity of IPNV vaccines. The virulent strain for inactivated vaccines elicited the highest level of virus neutralization (VN) titers and ELISA antibodies. Interestingly, differences in immunogenicity were not reflected in differences in post challenge survival percentages (PCSP) for oil-adjuvanted, inactivated vaccines but clearly so for live vaccines (TAT and PTA). Further post challenge viral carrier state correlated inversely with VN titers at challenge for inactivated vaccines and prevalence of pathology in target organs inversely correlated with protection for live vaccines. Overall, our findings show that a few residues localized on the VP2-capsid are important for immunogenicity of IPNV vaccines.

Autoantibodies against exocrine pancreas in Crohn's disease are directed against two antigens: the glycoproteins CUZD1 and GP2.

BACKGROUND: Autoantibodies against exocrine pancreas (PAb) have been reported to be pathognomonic markers of Crohn's disease (CD). Recently, the glycoprotein GP2 has been proposed as the exclusive target for PAb but two equally prevalent binding patterns can be observed in the indirect immunofluorescence test (IIFT) using cryosections of human pancreas: a reticulogranular and a droplet pattern. AIM: To identify autoantigens corresponding to the staining patterns. METHODS: Different lectins were screened for their ability to immobilize PAb-reactive glycoproteins from cell free human pancreas. The glycoproteins were then purified via UEA-I affinity chromatography and identified by mass spectrometry. The two candidate autoantigens were separately expressed in HEK293 cells, and the recombinant cells applied as substrates in IIFT to analyze sera from 96 patients with CD, 89 controls and hybridoma supernatants during the generation of murine monoclonal antibodies. RESULTS: The UEA-I eluate was able to neutralize PAb reactivity of both patterns in IIFT. It contained two major constituents which were identified as the glycoproteins CUZD1 and GP2. With the recombinant cells, 35.4% of the CD patients exhibited positive reactions (CUZD1 alone 19.8%, GP2 alone 9.4%, and both antigens 6.2%). The reaction with the CUZD1 expressing cells was strictly correlated to the reticulogranular pattern, whereas the antibodies causing the droplet pattern stained the GP2 expressing cells. Antigen-capture ELISA using the newly generated monoclonal antibodies against CUZD1 and GP2 verified this relationship. CONCLUSIONS: The concordant reactivities of the different platforms can be regarded as a proof for the authenticity of the two identified autoantigens.

The ER chaperone GRP78 is associated with the severity of cerulein-induced pancreatic inflammation via regulating apoptosis of pancreatic acinar cells.

BACKGROUND/AIMS: To study the potential role of the 78kDa glucose regulated protein (GRP78) in the pathogenesis of acute pancreatitis (AP) in vitro. METHODOLOGY: AR42J cells were stimulated by cerulein or cerulein plus lipoplysaccharide (LPS). The severity of pancreatic inflammation was evaluated by amylase, lipase, TNF-a, and IL-6. Apoptosis was determined by flow cytometry; the expressions of apoptotic genes, GRP78 and the downstream molecules were determined by real-time quantitative PCR and Western blot. RESULTS: After cerulein stimulation, the levels of amylase, lipase, TNF-a and IL-6 were all increased, with a more pronounced increase after cerulein plus LPS stimulation. Apoptosis was different in two cell models, high apoptosis in cerulein group; whereas cerulein plus LPS induced relatively less apoptosis. Apoptotic gene expressions revealed more pronounced increase in the cerulein group than those in cerulein plus LPS group. The expressions of GRP78 and downstream molecules were different in two cell models. GRP78 expression was down-regulated in cerulein group and upregulated in cerulein plus LPS group. CONCLUSIONS: GRP78 expression was associated with apoptosis and the severity of cerulein-induced pancreatic inflammation, indicating that GRP78 might prevent apoptosis in pancreatic acinar cells thereby deteriorating the severity of AP.

Pancreatic autoantibodies and autoantibodies against goblet cells in pediatric patients with inflammatory bowel disease.

BACKGROUND: Significance of pancreatic autoantibodies determined by using exocrine pancreas (PAB) and antibodies against recombinant pancreas antigen (rPAB), as well as the importance of autoantibodies against goblet cells (GAB), is not known in pediatric patients with inflammatory bowel disease (IBD). Our aim was to determine the complex analysis of PAB, rPAB, GAB, antibodies against Saccharomyces cerevisiae, and perinuclear components of neutrophils in pediatric patients with IBD. Moreover, association with NOD2/CARD15 and disease phenotype was determined. METHODS: A total of 152 pediatric patients (median age 13.9 years) with IBD (103 patients with Crohn disease [CD] and 49 patients with ulcerative colitis [UC]) and 104 controls were included. Serum autoantibodies were determined by indirect immunofluorescence assay. NOD2/CARD15 variants were tested by polymerase chain reaction/restriction fragment length polymorphism. RESULTS: The presence of PAB and rPAB was significantly higher in CD (34% and 35.9%) and in UC (20.4% and 24.5%) compared with pediatric control cohort (0% and 0%, P<0.0001). In addition, GAB positivity was significantly increased in patients with UC in comparison with CD and controls, respectively (UC, 12.2%; CD, 1.9%; controls, 1.9%; P=0.02). Specificity of PAB and rPAB was 100%; however, sensitivity was low. The combination of PAB and/or antibodies against Saccharomyces cerevisiae/perinuclear components of neutrophils improved the sensitivity of serological markers in CD (87.4%) and in UC (79.6%); specificities were 89.3% and 93.2%, respectively. Pancreatic autoantibodies (PAB, rPAB) and GAB were not related to clinical presentation, medical therapy, or need for surgery in CD or in UC. CONCLUSIONS: Pancreatic autoantibodies and GAB were specific for IBD, but the sensitivity was limited as well because there was lack of correlation with clinical phenotype. Combinations of these antibodies have shown increased sensitivity; therefore, it may be recommended in the diagnostic procedure of IBD.

[Sjögren's syndrome and pancreatic affection]. / Afección pancreática en el síndrome de sjögren.

Sjögren's syndrome (SS) is an autoimmune disorder affecting primarily the exocrine glands, leading to keratoconjunctivitis sicca (KCS) and xerostomia, but that can also include extraglandular features(1). Due the anatomical, physiological and pathological similarity between the pancreas and the salivary glands, it has been described that the pancreas it is not exempt from the damage produced by this syndrome. Some authors have assessed pancreatic involvement of SS by analyzing the histopathological changes, evaluating the pancreatic endocrine and exocrine function (serum pancreatic enzymes, elastase, lipase or trypsin determinations, N-benzoyl-L-tyrosyl-para-aminobenzoic acid excretion test, etc), searching specific pancreatic antibodies (antiductal) or performing endoscopic retrograde colangiopancreatography or noninvasive imaging studies such as computed tomography or ultrasound. Herein we review the literature regarding the prevalence and type of pancreatic involvement in the SS and we discuss the differential diagnosis with multiorganic Lymphoproliferative Syndrome.

TNF-alpha-dependent regulation of acute pancreatitis severity by Ly-6C(hi) monocytes in mice.

The roles of monocytes/macrophages and their mechanisms of action in the regulation of pancreatitis are poorly understood. To address these issues, we have employed genetically altered mouse strains that either express the human diphtheria toxin receptor (DTR) coupled to the CD11b promoter or have global deletion of TNF-α. Targeted, conditional depletion of monocytes/macrophages was achieved by administration of diphtheria toxin (DT) to CD11b-DTR mice. We show that in the absence of DT administration, pancreatitis is associated with an increase in pancreatic content of Ly-6C(hi) monocytes/macrophages but that this response is prevented by prior administration of DT to CD11b-DTR mice. DT administration also reduces pancreatic edema and acinar cell injury/necrosis in two dissimilar experimental models of acute pancreatitis (a secretagogue-induced model and a model elicited by retrograde pancreatic duct infusion of sodium taurocholate). In the secretagogue-elicited model, the DT-induced decrease in pancreatitis severity is reversed by adoptive transfer of purified Ly-6C(hi) monocytes harvested from non-DT-treated CD11b-DTR mice or by the transfer of purified Ly-6C(hi) monocytes harvested from TNF-α(+/+) donor mice, but it is not reversed by the transfer of Ly-6C(hi) monocytes harvested from TNF-α(-/-) donors. Our studies indicate that the Ly-6C(hi) monocyte subset regulates the severity of pancreatitis by promoting pancreatic edema and acinar cell injury/necrosis and that this phenomenon is dependent upon the expression of TNF-α by those cells. They suggest that therapies targeting Ly-6C(hi) monocytes and/or TNF-α expression by Ly-6C(hi) monocytes might prove beneficial in the prevention or treatment of acute pancreatitis.

Chronic stress sensitizes rats to pancreatitis induced by cerulein: role of TNF-α.

AIM: To investigate chronic stress as a susceptibility factor for developing pancreatitis, as well as tumor necrosis factor-α (TNF-α) as a putative sensitizer. METHODS: Rat pancreatic acini were used to analyze the influence of TNF-α on submaximal (50 pmol/L) cholecystokinin (CCK) stimulation. Chronic restraint (4 h every day for 21 d) was used to evaluate the effects of submaximal (0.2 µg/kg per hour) cerulein stimulation on chronically stressed rats. RESULTS: In vitro exposure of pancreatic acini to TNF-α disorganized the actin cytoskeleton. This was further increased by TNF-α/CCK treatment, which additionally reduced amylase secretion, and increased trypsin and nuclear factor-κB activities in a protein-kinase-C δ and ε-dependent manner. TNF-α/CCK also enhanced caspases' activity and lactate dehydrogenase release, induced ATP loss, and augmented the ADP/ATP ratio. In vivo, rats under chronic restraint exhibited elevated serum and pancreatic TNF-α levels. Serum, pancreatic, and lung inflammatory parameters, as well as caspases'activity in pancreatic and lung tissue, were substantially enhanced in stressed/cerulein-treated rats, which also experienced tissues' ATP loss and greater ADP/ATP ratios. Histological examination revealed that stressed/cerulein-treated animals developed abundant pancreatic and lung edema, hemorrhage and leukocyte infiltrate, and pancreatic necrosis. Pancreatitis severity was greatly decreased by treating animals with an anti-TNF-α-antibody, which diminished all inflammatory parameters, histopathological scores, and apoptotic/necrotic markers in stressed/cerulein-treated rats. CONCLUSION: In rats, chronic stress increases susceptibility for developing pancreatitis, which involves TNF-α sensitization of pancreatic acinar cells to undergo injury by physiological cerulein stimulation.