Inflammatory cells regulate p53 and caspases in acute pancreatitis

Oxidative stress and acute pancreatitis (Review)

Acute pancreatitis (AP) is a common inflammatory disorder of the exocrine pancreas that causes severe morbidity and mortality. Although the pathophysiology of AP is poorly understood, a substantial body of evidence suggests some critical events for this disease, such as dysregulation of digestive enzyme production, cytoplasmic vacuolization, acinar cell death, edema formation, and inflammatory cell infiltration into the pancreas. Oxidative stress plays a role in the acute inflammatory response. The present review clarified the role of oxidative stress in the occurrence and development of AP by introducing oxidative stress to disrupt cellular Ca2+ balance and stimulating transcription factor activation and excessive release of inflammatory mediators for the application of antioxidant adjuvant therapy in the treatment of AP.

p53 inhibitor iASPP is an unexpected suppressor of KRAS and inflammation-driven pancreatic cancer

Oncogenic KRAS activation, inflammation and p53 mutation are key drivers of pancreatic cancer (PC) development. Here we report iASPP, an inhibitor of p53, as a paradoxical suppressor of inflammation and oncogenic KRAS^G12D-driven PC tumorigenesis. iASPP suppresses PC onset driven by KRAS^G12D alone or KRAS^G12D in combination with mutant p53^R172H. iASPP deletion limits acinar-to-ductal metaplasia (ADM) in vitro but accelerates inflammation and KRAS^G12D-induced ADM, pancreatitis and PC tumorigenesis in vivo. KRAS^G12D/iASPP^Δ8/Δ8 tumours are well-differentiated classical PCs and their derivative cell lines form subcutaneous tumours in syngeneic and nude mice. Transcriptomically, either iASPP deletion or p53 mutation in the KRAS^G12D background altered the expression of an extensively overlapping gene set, comprised primarily of NF-κB and AP1-regulated inflammatory genes. All these identify iASPP as a suppressor of inflammation and a p53-independent oncosuppressor of PC tumorigenesis.

Therapeutic effect of rupatadine against l-arginine-induced acute pancreatitis in rats: role of inflammation

Acute pancreatitis (AP) is an abrupt inflammatory disorder causing high morbidity and mortality. As AP is an insidious medical emergency, a curative modality is required instead of a preventive measure. Thus, we investigated the possible curative effect of rupatadine on a rat model of AP. Rupatadine is a potent histamine receptor 1 (H1R) and platelet-activating factor (PAF) blocker. We used four groups of six Wistar rats as follows: the control group received vehicle; the rupatadine control group received rupatadine as 6 mg/kg orally; the AP group received l-arginine intraperitoneally, and the treatment group received rupatadine at 1, 6, and 24 h after l-arginine injection. The levels of serum amylase, pancreatic oxidative parameters, and pancreatic cytokines were measured. PAF, histamine, and myeloperoxidase levels were determined in the pancreas. Histopathological and immunohistochemical examinations were performed to determine nuclear factor kappa-B (NF-κB) and caspase 3 expressions. Oxidative damage and severe inflammation were detected in the pancreas of the AP group. Rupatadine reduced the oxidative damage and the levels of proinflammatory cytokines, PAF, histamine, myeloperoxidase, NF-κB, and caspase 3 expressions. It restored the pancreatic acini to almost normal condition. Rupatadine induced important anti-inflammatory and antiapoptotic effects against l-arginine-induced AP.

Role of Interleukin-17 in Acute Pancreatitis

Acute pancreatitis (AP) is a leading cause of death and is commonly accompanied by systemic manifestations that are generally associated with a poor prognosis. Many cytokines contribute to pancreatic tissue damage and cause systemic injury. Interleukin-17 (IL-17) is a cytokine that may play a vital role in AP. Specifically, IL-17 has important effects on the immune response and causes interactions between different inflammatory mediators in the AP-related microenvironment. In this literature review, we will discuss the existing academic understanding of IL-17 and the impacts of IL-17 in different cells (especially in acinar cells and immune system cells) in AP pathogenesis. The clinical significance and potential mechanisms of IL-17 on AP deterioration are emphasized. The evidence suggests that inhibiting the IL-17 cytokine family could alleviate the pathogenic process of AP, and we highlight therapeutic strategies that directly or indirectly target IL-17 cytokines in acute pancreatitis.

Pitfalls in AR42J-model of cerulein-induced acute pancreatitis

Background

AR42J are immortalized pancreatic adenocarcinoma cells that share similarities with pancreatic acinar cells. AR42J are often used as a cell-culture model of cerulein (CN)-induced acute pancreatitis (AP). Nevertheless, it is controversial how to treat AR42J for reliable induction of AP-like processes. Gene knockout and/or overexpression often remain challenging, as well. In this study, we demonstrate conditions for a reliable induction of proinflammatory markers upon CN treatment in AR42J and high transfection efficacy using Glyoxalase-I (Glo-I) as a target of interest.

Methods

Effects of dexamethasone (dexa) and CN on cell morphology and amylase secretion were analyzed via ELISA of supernatant. IL-6, TNF-α and NF-κB-p65 were measured via qRT-PCR, ELISA and Western Blot (WB). Transfection efficacy was determined by WB, qRT-PCR and immune fluorescence of pEGFP-N1-Glo-I-Vector and Glo-I-siRNA.

Results

Treatment of AR42J with 100 nm dexa is mandatory for differentiation to an acinar-cell-like phenotype and amylase production. CN resulted in secretion of amylase but did not influence amylase production. High levels of CN-induced amylase secretion were detected between 3 and 24 hours of incubation. Treatment with LPS alone or in combination with CN did not influence amylase release compared to control or CN. CN treatment resulted in increased TNF-α production but not secretion and did not influence IL-6 mRNA. CN-induced stimulation of NF-κB was found to be highest on protein levels after 6h of incubation. Transient transfection was able to induce overexpression on protein and mRNA levels, with highest effect after 12 to 24 hours. Gene-knockdown was achieved by using 30 pmol of siRNA leading to effective reduction of protein levels after 72 hours. CN did not induce amylase secretion in AR42J cell passages beyond 35.

Conclusion

AR42J cells demonstrate a reliable in-vitro model of CN-induced AP but specific conditions are mandatory to obtain reproducible data.

Resveratrol supplementation and acute pancreatitis: A comprehensive review

Resveratrol, a natural polyphenolic ingredient extracted from herbs, suppresses oxidative stress and inflammation. We performed a comprehensive review to find any evidence about the effects of Resveratrol on acute pancreatitis (AP). Resveratrol has been found to directly impact cytokine generation. As these factors play a crucial role in the pathophysiology of AP, resveratrol might attenuate AP and its complications. Mechanistically, resveratrol exerts its pharmacological effects through anti-inflammatory and antioxidant mechanisms via interaction with different signaling molecules and transcription factors. Indeed, resveratrol might prove to be an effective therapeutic component for AP treatment in the future. In this review, we shed light on potential most recent pathways through which resveratrol might impact the management and control of AP.

P53 Activated by ER Stress Aggravates Caerulein-Induced Acute Pancreatitis Progression by Inducing Acinar Cell Apoptosis

BACKGROUND AND AIMS

Acute pancreatitis (AP) is a severe pancreatic disorder that remains associated with high mortality due to a lack of effective drugs and management strategies. This study aimed to investigate the molecular pathogenic mechanisms of AP involving p53 and endoplasmic reticulum (ER) stress pathways.

METHODS

Expression of PRSS1 and p53 in human AP tissues was detected by immunohistochemistry and Western blotting. AP was induced with caerulein in humanized PRSS1 transgenic mice, and its severity was verified by histological imaging, evaluation of edema, serum amylase, and trypsin activity assays. A transferase-mediated d-UTP nick end-labeling assay was performed to evaluate acinar cell apoptosis associated with AP. The expression of ER stress genes was assessed by quantitative RT-PCR (qRT-PCR) and Western blotting.

RESULTS

PRSS1 and p53 were highly expressed in human AP tissues. Expression of human PRSS1 in caerulein-treated mice induced significant acinar cell apoptosis and AP progression. P53 knockout significantly suppressed AP progression in humanized PRSS1 transgenic mice. The ER stress pathway was activated by PRSS1 and mediated the progression of AP in mouse pancreatic tissues. Application of a p53 inhibitor effectively ameliorated caerulein-induced AP in PRSS1 transgenic mice, while a p53 activator promoted the progression of AP.

CONCLUSION

P53, which was activated by the ER stress pathway, promoted the progression of AP in mice expressing PRSS1 by inducing acinar cell apoptosis.

Targeting MDM2 for novel molecular therapy: Beyond oncology

The murine double minute 2 (MDM2) oncogene exerts major oncogenic activities in human cancers; it is not only the best-documented negative regulator of the p53 tumor suppressor, but also exerts p53-independent activities. There is an increasing interest in developing MDM2-based targeted therapies. Several classes of MDM2 inhibitors have been evaluated in preclinical models, with a few entering clinical trials, mainly for cancer therapy. However, noncarcinogenic roles for MDM2 have also been identified, demonstrating that MDM2 is involved in many chronic diseases and conditions such as inflammation and autoimmune diseases, dementia and neurodegenerative diseases, heart failure and cardiovascular diseases, nephropathy, diabetes, obesity, and sterility. MDM2 inhibitors have been shown to have promising therapeutic efficacy for treating inflammation and other nonmalignant diseases in preclinical evaluations. Therefore, targeting MDM2 may represent a promising approach for treating and preventing these nonmalignant diseases. In addition, a better understanding of how MDM2 works in nonmalignant diseases may provide new biomarkers for their diagnosis, prognostic prediction, and monitoring of therapeutic outcome. In this review article, we pay special attention to the recent findings related to the roles of MDM2 in the pathogenesis of several nonmalignant diseases, the therapeutic potential of its downregulation or inhibition, and its use as a biomarker.

Early Prediction of Persistent Organ Failure by Circulating Endothelial Progenitor Cells in Patients With Acute Pancreatitis

INTRODUCTION

Increased circulating endothelial progenitor cells (cEPC) have been observed in patients with vascular injury associated with sepsis and acute lung injury. However, a role for cEPC in severe acute pancreatitis (SAP) remains unclear. We therefore conducted a prospective study to study whether the quantities of cEPC can predict persistent organ failure (POF) in patients with predicted SAP.

METHODS

A total of 42 predicted SAP patients who were admitted within 24 h after symptom onset and 10 healthy control subjects were enrolled in our study. The proportions of cEPC were analyzed based on flow cytometry simultaneously. Vascular endothelial growth factor (VEGF) levels were measured by enzyme-linked immunosorbent assay.

RESULTS

The percentage of cEPC was significantly higher in patients with predicted SAP compared with healthy controls. Similarly, the levels of VEGF in peripheral blood were also significantly higher in predicted SAP patients than in the controls. Notably, patients with POF had lower proportion of cEPC compared with patients with transient organ failure (TOF). In contrast, patients with POF had a significantly higher level of VEGF compared with TOF. Of note, the percentages of cEPC were significantly inversely correlated with disease severity scores. More importantly, cEPC showed an excellent discriminative power for predicting POF among predicted SAP patients, whereas plasma VEGF and disease severity scores showed moderate accuracy in predicting future POF.

CONCLUSIONS

Peripheral EPC as a novel biomarker is elevated and may aid to predict the development of POF in patients with predicted SAP.

Atrial natriuretic peptide attenuates endoplasmic reticulum stress in experimental acute pancreatitis

Increasing evidence shows that the endoplasmic reticulum (ER) stress is an early event that injures pancreatic acinar cells and contributes to the pathogenesis of acute pancreatitis. In the present work we sought to establish whether atrial natriuretic peptide (ANP) alleviated ER stress in rats with cerulein-induced pancreatitis. The major components of the unfolded protein response (UPR) and their downstream effectors were assessed by immunoblotting or fluorimetry and the ultrastructure of ER evaluated by electron transmission microscopy. Cross-talk with autophagy was evaluated by beclin-1 expression. ANP reduced binding immunoglobulin protein (Bip) expression (UPR major controller) which under non-stress conditions keeps inactive the stress sensor proteins: protein kinase-like ER kinase (PERK), inositol-requiring enzyme-1 (IRE1) and activating transcription factor 6 (ATF6). Although ANP did not change PERK expression it decreased p-eIF2α and enhanced downstream effector CHOP, suggesting that ANP stimulates ER-dependent apoptosis. In accordance, ANP also decreased Bcl2 expression and enhanced proapoptotic proteins Bax and Bak. The atrial peptide enhanced ATF6 expression and although it did not affect IRE1/sXBP1 signaling, it increased caspase-2 activity, also involved in ER-dependent apoptosis. Furthermore, ANP decreased beclin-1 expression. The ultrastructure of the RE revealed decreased swelling and conserved ribosomes in the presence of ANP. Present findings support that ANP alleviates ER stress in acute pancreatitis by modulating the three branches of the UPR and stimulates ER-dependent apoptosis. Gaining insights into the modulation of ER stress may help to develop specific therapeutic strategies for acute pancreatitis and/or medical interventions at risk of its developing like endoscopic retrograde cholangiopancreatography.

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

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

Resveratrol protects against L-arginine-induced acute necrotizing pancreatitis in mice by enhancing SIRT1-mediated deacetylation of p53 and heat shock factor 1

Acute necrotizing pancreatitis (ANP) is a common severe critical illness with a high mortality rate. Resveratrol, a polyphenol compound derived from various plants such as grape skin, peanut, berry and veratrum, exhibits multiple biological activities, especially potent anti‑inflammatory activity, but its effect on ANP has not yet been fully elucidated. The present study aimed to investigate the effects of resveratrol on L-arginine-induced ANP and the possible mechanisms. A mouse model of ANP was established by 2 hourly intraperitoneal injections of 8% L-arginine (4 g/kg). Then the mice were treated by intragastric administration of resveratrol (80 mg/kg) every 12 h immediately after the second injection of L-arginine. Mice with ANP showed increased apoptosis of pancreatic acinar cells, pancreatic myeloperoxidase activity, serum lactate dehydrogenase activity, amylase, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) levels as well as decreased serum IL-10 level, pancreatic expression of heat shock factor 1 (HSF1), sirtuin 1 (SIRT1) and p53, but the ratio of acetylated HSF1 and p53 was markedly increased. Resveratrol enhanced the survival rate of mice with ANP from 47.8 to 71.4% and obviously restored the changes in mice with ANP as mentioned above. Additionally, interactions between SIRT1 and p53 and between SIRT1 and HSF1 in the pancreas of the mice were confirmed by co-immunoprecipitation. These data suggest that resveratrol protects against L-arginine-induced ANP, which may be related to the enhancement of SIRT1-mediated deacetylation of p53 and HSF1.

Update on innate immunity and perspectives on metabolite regulation in acute pancreatitis

PURPOSE OF REVIEW

Acute pancreatitis is a major cause of gastrointestinal morbidity for which specific therapy is greatly needed to prevent progression to and induce resolution of severe disease.

RECENT FINDINGS

Innate immune components and metabolite signaling are recently identified as strong determinants of disease severity and resolution in acute pancreatitis and this work will be discussed herein.

SUMMARY

Targeting innate immune cell populations and metabolite signaling pathways in acute pancreatitis may result in broader and ultimately more efficacious re-direction of the inflammatory programme toward disease resolution and improved clinical outcomes.

Acute Pancreatitis-Progress and Challenges: A Report on an International Symposium

An international symposium entitled "Acute pancreatitis: progress and challenges" was held on November 5, 2014 at the Hapuna Beach Hotel, Big Island, Hawaii, as part of the 45th Anniversary Meeting of the American Pancreatic Association and the Japanese Pancreas Society. The course was organized and directed by Drs. Stephen Pandol, Tooru Shimosegawa, Robert Sutton, Bechien Wu, and Santhi Swaroop Vege. The symposium objectives were to: (1) highlight current issues in management of acute pancreatitis, (2) discuss promising treatments, (3) consider development of quality indicators and improved measures of disease activity, and (4) present a framework for international collaboration for development of new therapies. This article represents a compilation and adaptation of brief summaries prepared by speakers at the symposium with the purpose of broadly disseminating information and initiatives.

Framework for interpretation of trypsin-antitrypsin imbalance and genetic heterogeneity in pancreatitis

Early intracellular premature trypsinogen activation was interpreted as the key initiator of pancreatitis. When the balance in the homeostasis of trypsin and antitrypsin system is disequilibrated, elevated aggressive enzymes directly attack the pancreatic tissue, which leads to pancreatic destruction and inflammation. However, trypsin alone is not enough to cause complications in pancreatitis, which may play a crucial role in modulating signaling events in the initial phase of the disease. NFκB activation is the major inflammatory pathway involved in the occurrence and development of pancreatitis and it can be induced by intrapancreatic activation of trypsinogen. Synthesis of trypsinogen occurs in endoplasmic reticulum (ER), and ER stress is an important early acinar cell event. Components of ER stress response are known to be able to trigger cell death as well as NFκB signaling cascade. The strongest evidence supporting the trypsin-centered theory is that gene mutations, which lead to the generation of more trypsin, or reduce the activity of trypsin inhibitors or trypsin degradation, are associated with pancreatitis. Thus, trypsin-antitrypsin imbalance may be the first step leading to pancreatic autodigestion and inducing other pathways. Continued experimental studies are necessary to determine the specific relationships between trypsin-antitrypsin imbalance and genetic heterogeneity in pancreatitis. In this article, we review the latest advances that contributed to the understanding of the basic mechanisms behind the occurrence and development of pancreatitis with a focus on the interpretation of trypsin-antitrypsin imbalance and their relationships with other inflammation pathways. We additionally highlight genetic predispositions to pancreatitis and possible mechanisms associated with them.

EPIC combined with NLR vs BISAP for early prediction of severity of acute pancreatitis

AIM: To compare the value extrapancreatic inflammation on abdominal computed tomography (EPIC) combined with neutropil-lymphocyte rate (NLR) vs bedside index for severity in acute pancreatitis (BISAP) in early prediction of severity of acute pancreatitis (AP).

METHODS: The clinical, laboratory and CT data obtained on admission (within first 24 h of hospitalization) for 358 patients with AP who were hospitalized from January 2010 to April 2014 were analyzed. The EPIC, NLR, BISAP and modified Marshall scores were calculated in all patients. The combined score was defined as EPIC score plus NLR score. AP was classified as mild AP (MAP), moderately severe AP (MSAP) and severe AP (SAP). The EPIC, NLR, BISAP scores and combined score were compared between groups. The correlation of these scores with severity of AP was analyzed using Spearman test. The AUC, sensitivity, specificity, accuracy, positive predictive value, negative predictive value and Youden index of these scores in early prediction of severity of AP were calculated.

RESULTS: There were 303 patients with MAP (mild group) and 55 patients with MSAP or SAP (severe group). The EPIC, NLR, BISAP and combined scores in the severe group were significantly higher than those in the mild group (4.200 ± 1.393 vs 1.373 ± 1.333, 14.358 ± 5.908 vs 7.929 ± 4.514, 2.655 ± 0.985 vs 0.993 ± 0.843, 5.164 ± 1.385 vs 1.819 ± 1.493, P = 0.000 for all). The Spearman correlation coefficients between AP severity and EPIC, NLR, BISAP and combined scores were 0.529, 0.406, 0.546 and 0.554, respectively (P = 0.000 for all). The AUCs of EPIC, NLR, BISAP and combined scores for predicting AP severity were 0.914 (95%CI: 0.867-0.961), 0.825 (95%CI: 0.778-0.872), 0.911 (95%CI: 0.863-0.960) and 0.938 (95%CI: 0.900-0.975), respectively (P = 0.000 for all). The sensitivity, specificity, accuracy, positive predictive value, negative predictive value and Youden index of BISAP score and combined score for predicting AP severity were 90.909% vs 85.455%, 80.528% vs86.469%, 82.123% vs 86.313%, 45.872% vs 53.409%, 97.992% vs 97.037%, and 0.714 vs 0.719, respectively.

CONCLUSION: The combined score of EPIC and NLR is easy to obtain and simple. The AUC of the combined score for predicting severity of early AP is larger than that of BISAP score. The specificity and accuracy of the combined score in predicting severity of early AP are higher than those of other indexes.

The heparin-binding protein interactome in pancreatic diseases

BACKGROUND

The cellular microenvironment plays an important role in the regulation of homoeostasis and is a source of potential biomarkers and drug targets. In a genome-wide analysis the extracellular proteins that bind to heparin (HBPs) have been shown to form highly modular and interconnected extracellular protein regulatory networks. Using a systems biology approach, we have investigated the role of HBP networks in the normal pancreas and pancreatic digestive diseases.

METHODS

Lists of mRNAs encoding for HBPs associated with the normal pancreas (NP), acute pancreatitis (AP), chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) were obtained using public databases and publications. Networks of the putative protein interactomes derived from mRNA expression data of HBPs were built and analysed using cluster analysis, gene ontology term enrichment and canonical pathways analysis.

RESULTS

The extracellular heparin-binding putative protein interactomes in the pancreas were better connected than their non heparin-binding counterparts, having higher clustering coefficients in the normal pancreas (0.273), acute pancreatitis (0.457), chronic pancreatitis (0.329) and pancreatic ductal adenocarcinoma (0.269). 'Hepatic Fibrosis/Hepatic Stellate Cell Activation' appears to be a significant canonical pathway in pancreatic homoeostasis in health and disease with a large number of important HBPs.

CONCLUSIONS

Our analyses clearly demonstrate that HBPs form disease-specific and highly connected networks that can be explored for potential biomarkers and as collective drug targets via the modification of heparin binding properties.

Inflammation, autophagy, and obesity: common features in the pathogenesis of pancreatitis and pancreatic cancer

Inflammation and autophagy are cellular defense mechanisms. When these processes are deregulated (deficient or overactivated) they produce pathologic effects, such as oxidative stress, metabolic impairments, and cell death. Unresolved inflammation and disrupted regulation of autophagy are common features of pancreatitis and pancreatic cancer. Furthermore, obesity, a risk factor for pancreatitis and pancreatic cancer, promotes inflammation and inhibits or deregulates autophagy, creating an environment that facilitates the induction and progression of pancreatic diseases. However, little is known about how inflammation, autophagy, and obesity interact to promote exocrine pancreatic disorders. We review the roles of inflammation and autophagy, and their deregulation by obesity, in pancreatic diseases. We discuss the connections among disordered pathways and important areas for future research.

CCR2 knockout exacerbates cerulein-induced chronic pancreatitis with hyperglycemia via decreased GLP-1 receptor expression and insulin secretion

Glucagon-like peptide-1 (GLP-1) promotes insulin release; however, the relationship between the GLP-1 signal and chronic pancreatitis is not well understood. Here we focus on chemokine (C-C motif) ligand 2 (CCL2) and its receptor (CCR2) axis, which regulates various immune cells, including macrophages, to clarify the mechanism of GLP-1-mediated insulin secretion in chronic pancreatitis in mice. One and multiple series of repetitive cerulein administrations were used to induce acute and chronic cerulein pancreatitis, respectively. Acute cerulein-administered CCR2-knockout (KO) mice showed suppressed infiltration of CD11b(+)Gr-1(low) macrophages and pancreatic inflammation and significantly upregulated insulin secretion compared with paired wild-type (WT) mice. However, chronic cerulein-administered CCR2-KO mice showed significantly increased infiltration of CD11b(+)/Gr-1(-) and CD11b(+)/Gr-1(high) cells, but not CD11b(+)/Gr-1(low) cells, in pancreas with severe inflammation and significantly decreased insulin secretion compared with their WT counterparts. Furthermore, although serum GLP-1 levels in chronic cerulein-administered WT and CCR2-KO mice were comparably upregulated after cerulein administrations, GLP-1 receptor levels in pancreases of chronic cerulein-administered CCR2-KO mice were significantly lower than in paired WT mice. Nevertheless, a significantly higher hyperglycemia level in chronic cerulein-administered CCR2-KO mice was markedly restored by treatment with a GLP-1 analog to a level comparable to the paired WT mice. Collectively, the CCR2/CCL2 axis-mediated CD11b(+)-cell migration to the pancreas is critically involved in chronic pancreatitis-mediated hyperglycemia through the modulation of GLP-1 receptor expression and insulin secretion.

Nuclear factor-κB in pancreatitis: Jack-of-all-trades, but which one is more important?

See “Deletion of IκBα activates RelA to reduce acute pancreatitis in mice through up-regulation of Spi2A,” by Neuhöfer P, Liang S, Einwächter H, et al, on page 192; and “Activation of nuclear factor-κB in acinar cells increases the severity of pancreatitis in mice,” by Huang H, Liu Y, Daniluk J, et al, on page 202.

Protective effect of low-molecular-weight heparin on pancreatic encephalopathy in severe acute pancreatic rats

BACKGROUND AND AIMS

Pancreatic encephalopathy (PE) is a severe complication and significant cause of death in patients with severe acute pancreatitis (SAP). We have reported previously that low-molecular-weight heparin (LMWH) treatment could reduce incidence of PE in SAP patients. Our objective here was to investigate the protective effect of LMWH and its mechanism on PE in SAP rats.

METHODS

SD rats were randomly divided into three groups: (1) Sham-operation (S) group, (2) SAP group, and (3) LMWH treatment (LMWH) group. LMWH was administrated 4 h after the SAP model conducted. The levels of serum amylase, myelin basic protein (MBP), tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), brain water content, occurrence of apoptosis, and pathological changes of pancreas and brain were measured at 1 day after models were set up in the SAP and S groups, and 1 day after LMWH treatment was administrated in the LMWH group.

RESULTS

(1) The levels of serum amylase, TNF-α, and IL-6 in the SAP group were increased significantly more than those in the S and LMWH groups (all P < 0.001), as were the levels of serum MBP in the SAP group compared to those in the S and LMWH groups (P < 0.01, <0.05 respectively). However, while the level of serum amylase and IL-6 in the LMWH group were significantly increased compared to those in the S group (P < 0.05, <0.001 respectively), the levels of TNF-α and MBP showed no significant difference between the LMWH and S groups (all P > 0.05). (2) The brain water content in the SAP group was significantly increased compared to the S group and LMWH group (P < 0.01, <0.05 respectively). (3) Neuronal apoptosis, demyelination, and mitochondrial vacuolation in neuronal cells were observed in the SAP group; in contrast, in the LMWH group, significantly lower rates of neuronal apoptosis, demyelination and mitochondrial edema were observed in neuronal cells.

CONCLUSIONS

The protective effect of LMWH on PE progression in SAP rats might result from inhibition of inflammatory activation and reduction of the occurrence of neuronal apoptosis.

Comparative evaluation of blood markers and extrapancreatic inflammatim on CT score in the early prediction of the severity of acute panereatitis

AIM: To compare the value of blood markers and extrapancreatic inflammation on CT score (EPIC) in early prediction of the severity of acute pancreatitis (AP).

METHODS: The clinical, laboratory and CT data obtained on admission (within 24 h of hospitalization) for 96 patients with AP who were hospitalized from September 2010 to September 2011 were analyzed. Severe AP (SAP) was defined as the presence of one or more of the following signs: mortality, persistent organ failure and/or admission ICU, and/or operation. Blood markers and EPIC were compared between SAP group and mild AP (MAP) using the t test. The correlation between blood markers, EPIC and severity of AP was analyzed. The value of blood markers and EPIC in predicting the severity of AP was assessed using receiver operation curve analysis. The sensitivity, positive predictive value and accuracy were also studied.

RESULTS: There were 20 patients with SAP and 76 patients with MAP. The levels of blood markers and EPIC in the SAP group were significantly higher than those in the MAP group [white blood cell (WBC): (15.16 ± 5.06) × 10⁹/L vs (11.05 ± 1.76) × 10⁹/L, neutrophil-lymphocyte ratio (NLR): 18.95 ± 12.13 vs 6.63 ± 3.44, high-sensitivity C-reactive protein (hs-CRP): 58.35 mg/L ± 20.47 mg/L vs 28.59 mg/L ± 12.92 mg/L, D-dimer (DD): 1596.95 μg/L ± 1409.05 μg/L vs 412.52 μg/L ± 316.66 μg/L, EPIC: 3.30 ± 0.86 vs 1.50 ± 0.96, all P = 0.000]. The Spearman correlation coefficients (rs) between severity of AP and WBC, NLR, hs-CRP, DD and EPIC were 0.419, 0.571, 0.568, 0.434 and 0.613, respectively (all P = 0.000). The area under the curve (AUC) of WBC, NLR, hs-CRP, DD and EPIC in predicting the severity of AP were 0.798 (0.670-0.925), 0.906 (0.830-0.981), 0.904 (0.838-0.970), 0.808 (0.638-0.938) and 0.917 (0.851-0.983), respectively. The predictive sensitivities were 70.00%, 85.00%, 85.00%, 75.00% and 85.00%; the positive predictive values were 58.33%, 73.91%, 51.52%, 48.39% and 72.00%; and the accuracies were 83.33%, 90.63%, 80.21%, 78.13% and 90.63%, respectively.

CONCLUSION: WBC and DD have a moderate value in predicting the severity of AP, while NLR, hs-CRP, and EPIC have a much higher value.

CCL2-induced migration and SOCS3-mediated activation of macrophages are involved in cerulein-induced pancreatitis in mice

BACKGROUND & AIMS

Acute pancreatitis is a common inflammatory disease mediated by damage to acinar cells and subsequent pancreatic inflammation with recruitment of leukocytes. We investigated the pathologic roles of innate immune cells, especially macrophages, in cerulein- and L-arginine-induced acute pancreatitis in mice.

METHODS

Acute pancreatitis was induced by sequential peritoneal administration of cerulein to mice. We determined serum concentrations of amylase and lipase, pancreatic pathology, and features of infiltrating mononuclear cells. We performed parabiosis surgery to assess the hemodynamics of pancreatic macrophages.

RESULTS

Almost all types of immune cells, except for CD11b(high)CD11c(-) cells, were detected in the pancreas of healthy mice. However, activated CD11b(high)CD11c(-) cells, including Gr-1(low) macrophages and Gr-1(high) cells (granulocytes and myeloid-derived suppressor cells), were detected in damaged pancreas after cerulein administration. CCL2(-/-) mice given cerulein injections developed significantly less severe pancreatitis, with less infiltration of CD11b(high)CD11c(-)Gr-1(low) macrophages, but comparable infiltration of myeloid-derived suppressor cells, compared with cerulein-injected wild-type mice. Parabiosis and bone marrow analyses of these mice revealed that the CD11b(high)CD11c(-)Gr-1(low) macrophages had moved out of the bone marrow. Furthermore, mice with macrophage-specific deletion of suppressor of cytokine signaling 3 given injections of cerulein developed less severe pancreatitis and Gr-1(low) macrophage produced less tumor necrosis factor-α than wild-type mice given cerulein, although the absolute number of CD11b(high)CD11c(-)Gr-1(low) macrophages was comparable between strains. Induction of acute pancreatitis by L-arginine required induction of macrophage migration by CCL2, via the receptor CCR2.

CONCLUSIONS

Cerulein induction of pancreatitis in mice involves migration of CD11b(high)CD11c(-)Gr-1(low) macrophage from the bone marrow (mediated by CCL2 via CCR2) and suppressor of cytokine signaling 3-dependent activation of macrophage. These findings might lead to new therapeutic strategies for acute pancreatitis.

Organellar dysfunction in the pathogenesis of pancreatitis

SIGNIFICANCE

Acute pancreatitis is an inflammatory disease of exocrine pancreas that carries considerable morbidity and mortality; its pathophysiology remains poorly understood. During the past decade, new insights have been gained into signaling pathways and molecules that mediate the inflammatory response of pancreatitis and death of acinar cells (the main exocrine pancreas cell type). By contrast, much less is known about the acinar cell organellar damage in pancreatitis and how it contributes to the disease pathogenesis.

RECENT ADVANCES

This review summarizes recent findings from our group, obtained on experimental in vivo and ex vivo models, which reveal disordering of key cellular organelles, namely, mitochondria, autophagosomes, and lysosomes, in pancreatitis. Our results indicate a critical role for mitochondrial permeabilization in determining the balance between apoptosis and necrosis in pancreatitis, and thus the disease severity. We further investigate how the mitochondrial dysfunction (and hence acinar cell death) is regulated by Ca(2+), reactive oxygen species, and Bcl-xL, in relation to specific properties of pancreatic mitochondria. Our results also reveal that autophagy, the principal cellular degradative, lysosome-driven pathway, is impaired in pancreatitis due to inefficient lysosomal function, and that impaired autophagy mediates two key pathological responses of pancreatitis-accumulation of vacuoles in acinar cells and the abnormal, intra-acinar activation of digestive enzymes such as trypsinogen.

CRITICAL ISSUES AND FUTURE DIRECTIONS

The findings discussed in this review indicate critical roles for mitochondrial and autophagic/lysosomal dysfunctions in the pathogenesis of pancreatitis and delineate directions for detailed investigations into the molecular events that underlie acinar cell organellar damage.

Molecular and cellular mechanisms of pancreatic injury

PURPOSE OF REVIEW

This review focuses on studies from the past year that highlight molecular and cellular mechanisms of pancreatic injury arising from acute and chronic pancreatitis.

RECENT FINDINGS

Factors that induce or ameliorate injury as well as cellular pathways involved have been examined. Causative or sensitizing factors include refluxed bile acids, hypercalcemia, ethanol, hypertriglyceridemia, and acidosis. In addition, the diabetes drug exendin-4 has been associated with pancreatitis, whereas other drugs may reduce pancreatic injury. The intracellular events that influence disease severity are better understood. Cathepsin-L promotes injury through an antiapoptotic effect, rather than by trypsinogen activation. In addition, specific trypsinogen mutations lead to trypsinogen misfolding, endoplasmic reticulum stress, and injury. Endogenous trypsin inhibitors and upregulation of proteins including Bcl-2, fibroblast growth factor 21, and activated protein C can reduce injury. Immune cells, however, have been shown to increase injury via an antiapoptotic effect.

SUMMARY

The current findings are critical to understanding how causative factors initiate downstream cellular events resulting in pancreatic injury. Such knowledge will aid in the development of targeted treatments for pancreatitis. This review will first discuss factors influencing pancreatic injury, and then conclude with studies detailing the cellular mechanisms involved.

Inhibition of acinar apoptosis occurs during acute pancreatitis in the human homologue DeltaF508 cystic fibrosis mouse

Previously, we found that the University of North Carolina cystic fibrosis (UNC-CF) mouse had more severe experimental acute pancreatitis (AP) than wild-type (WT) mice characterized by exuberant pancreatic inflammation and impaired acinar apoptosis. Because exon 10 CFTR gene mutations exhibit different phenotypes in tissues such as the mouse lung, we tested the hypothesis that DeltaF508-CF mice also develop severe AP associated with an antiapoptotic acinar phenotype, which requires indirect effects of the extracellular milieu. We used cerulein hyperstimulation models of AP. More severe pancreatitis occurred in cerulein-injected DeltaF508-CF vs. WT mice based on histological severity (P < 0.01) and greater neutrophil sequestration [P < 0.0001; confirmed by myeloperoxidase activity (P < 0.005)]. In dispersed acini cerulein-evoked necrosis was greater in DeltaF508-CF acini compared with WT (P < 0.05) and in WT acini pretreated with CFTR(inh)-172 compared with vehicle (P < 0.05). Cerulein-injected DeltaF508-CF vs. WT mice had less apoptosis based on poly(ADP-ribose) polymerase (PARP) cleavage (P < 0.005), absent DNA laddering, and reduced terminal deoxynucleotidyltransferase biotin-dUTP nick end labeling (TUNEL) staining (P < 0.005). Unexpectedly, caspase-3 activation was greater in DeltaF508-CF vs. WT acini at baseline (P < 0.05) and during AP (P < 0.0001). Downstream, DeltaF508-CF pancreas overexpressed the X-linked inhibitor of apoptosis compared with WT (P < 0.005). In summary, the DeltaF508-CF mutation, similar to the UNC-CF "null" mutation, causes severe AP characterized by an exuberant inflammatory response and impaired acinar apoptosis. Enhanced acinar necrosis in DeltaF508-CF occurs independently of extracellular milieu and correlates with loss of CFTR-Cl conductance. Although both exon 10 models of CF inhibit acinar apoptosis execution, the DeltaF508-CF mouse differs by increasing apoptosis signaling. Impaired transduction of increased apoptosis signaling in DeltaF508-CF acini may be biologically relevant to the pathogenesis of AP associated with CFTR mutations.