Novel antioxidant ameliorates the fibrosis and inflammation of cerulein-induced chronic pancreatitis in a mouse model

Arecae pericarpium water extract alleviates chronic pancreatitis by deactivating pancreatic stellate cells

Chronic pancreatitis (CP) is a chronic inflammatory disease of the pancreas with irreversible morphological changes. Arecae pericarpium (ARP), known to improve gastrointestinal disorders, has not yet been reported to inhibit fibrosis in CP. Therefore, we investigated the beneficial effects of ARP on cerulein-induced CP. Cerulein (50 μg/kg) was administered intraperitoneally to mice every hour, six times a day, four times a week for a total of 3 weeks to induce CP. To ascertain the prophylactic effects of ARP, ARP water extract (50, 100, or 200 mg/kg) or saline was administered intraperitoneally 1 h before the onset of CP. To determine the therapeutic effects of ARP, ARP water extract (200 mg/kg) or saline was administered for a total of 1 week or 2 weeks, starting 2 weeks or 1 week after the onset of CP. The pancreas was collected immediately for histological analysis. Additionally, to determine the effectiveness and mechanism of ARP in alleviating pancreatic fibrosis, pancreatic stellate cells (PSCs) were isolated. ARP treatment considerably improved glandular atrophy and inflammation and repressed collagen deposition in the pancreas. Furthermore, ARP water extract inhibited extracellular matrix (ECM) constituents such as alpha-smooth muscle actin (α-SMA), collagen I, and fibronectin 1 (FN1) in pancreatic tissue and PSCs. ARP also suppressed transforming growth factor-β (TGF-β) signaling by inhibiting Smad2 phosphorylation. Our study suggests that ARP exhibits anti-fibrotic effects in cerulein-induced CP by inhibiting TGF-β/Smad signaling.

Murine Chronic Pancreatitis Model Induced by Partial Ligation of the Pancreatic Duct Encapsulates the Profile of Macrophage in Human Chronic Pancreatitis

Immune responses are an integral part of the pathogenesis of pancreatitis. Studies applying the mouse model of pancreatitis induced by partial ligation of the pancreatic duct to explore the pancreatic immune microenvironment are still lacking. The aim of the present study is to explore the macrophage profile and associated regulatory mechanisms in mouse pancreatitis, as well as the correlation with human chronic pancreatitis (CP). In the present study, the mouse model of pancreatitis was induced by partial ligation of the pancreatic duct. Mice in the acute phase were sacrificed at 0, 4, 8, 16, 32, 72 h after ligation, while mice in the chronic phase were sacrificed at 7, 14, 21, 28 days after ligation. We found that the pancreatic pathological score, expression of TNF-α and IL-6 were elevated over time and peaked at 72h in the acute phase, while in the chronic phase, the degree of pancreatic fibrosis peaked at day 21 after ligation. Pancreatic M1 macrophages and pyroptotic macrophages showed a decreasing trend over time, whereas M2 macrophages gradually rose and peaked at day 21. IL-4 is involved in the development of CP and is mainly derived from pancreatic stellate cells (PSCs). The murine pancreatitis model constructed by partial ligation of the pancreatic duct, especially the CP model, can ideally simulate human CP caused by obstructive etiologies in terms of morphological alterations and immune microenvironment characteristics.

Targeting Fibrosis: The Bridge That Connects Pancreatitis and Pancreatic Cancer

Pancreatic fibrosis is caused by the excessive deposits of extracellular matrix (ECM) and collagen fibers during repeated necrosis to repair damaged pancreatic tissue. Pancreatic fibrosis is frequently present in chronic pancreatitis (CP) and pancreatic cancer (PC). Clinically, pancreatic fibrosis is a pathological feature of pancreatitis and pancreatic cancer. However, many new studies have found that pancreatic fibrosis is involved in the transformation from pancreatitis to pancreatic cancer. Thus, the role of fibrosis in the crosstalk between pancreatitis and pancreatic cancer is critical and still elusive; therefore, it deserves more attention. Here, we review the development of pancreatic fibrosis in inflammation and cancer, and we discuss the therapeutic strategies for alleviating pancreatic fibrosis. We further propose that cellular stress response might be a key driver that links fibrosis to cancer initiation and progression. Therefore, targeting stress proteins, such as nuclear protein 1 (NUPR1), could be an interesting strategy for pancreatic fibrosis and PC treatment.

Inhibitory Smads suppress pancreatic stellate cell activation through negative feedback in chronic pancreatitis

Background

Activation of pancreatic stellate cells (PSCs) is a key cause of chronic pancreatitis (CP), while inhibition of transforming growth factor-β (TGF-β) signaling renders PSCs inactive. Inhibitory Smads (I-Smads) impede TGF-β intracellular signaling and may provide a way to alleviate CP. Thus, we aimed to investigate the molecular mechanism of I-Smads in CP animals and freshly-isolated PSCs.

Methods

Sixteen male C57BL/6 mice were randomly divided into two groups; a control group (treated with saline) and a CP group (treated with caerulein) for 6 weeks. Masson’s staining was performed to identify fibrosis, and immunohistochemistry (IHC) was performed to measure the levels of Smad6 between the two groups. An improved method derived from internal digestion was used to isolate PSCs from male Sprague Dawley rats. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence staining were used to measure the messenger ribonucleic acid (mRNA) and protein levels of alpha-smooth muscle actin (α-SMA). Plasmids of I-Smads or SB431542 were transfected into freshly-isolated PSCs, and relative mRNA levels of marker genes were quantified by qRT-PCR. The two-tailed Student’s t-test was performed to assess significance.

Results

The Smad6 protein level was significantly higher in the pancreas tissue of CP mice compared to the control group. A large number of PSCs were isolated from rat pancreas using an improved isolating method and were confirmed by quiescent and active PSC markers including cluster differentiation antigen 133 (CD133), perilipin 2 (Plin2), α-SMA, Desmin, and collagen 1 (Col1). The mRNA levels of both Smad6 and Smad7 were down-regulated during freshly-isolated PSC activation. Over-expression of both Smad6 and Smad7 in freshly-isolated PSC reduced the mRNA level of α-SMA, glial fibrillary acidic protein (GFAP), Desmin, Col1, Col3, and fibronectin 1 (Fn1) significantly. SB431542 reduced the mRNA level of α-SMA, Col1, Col3, and Fn1 significantly in freshly-isolated PSCs.

Conclusions

This study demonstrated that CP promoted the expression of I-Smads, which suppressed the activation of freshly-isolated PSCs via a negative feedback loop.

Diversity and Biology of Cancer-Associated Fibroblasts

Efforts to develop anti-cancer therapies have largely focused on targeting the epithelial compartment, despite the presence of non-neoplastic stromal components that substantially contribute to the progression of the tumor. Indeed, cancer cell survival, growth, migration, and even dormancy are influenced by the surrounding tumor microenvironment (TME). Within the TME, cancer-associated fibroblasts (CAFs) have been shown to play several roles in the development of a tumor. They secrete growth factors, inflammatory ligands, and extracellular matrix proteins that promote cancer cell proliferation, therapy resistance, and immune exclusion. However, recent work indicates that CAFs may also restrain tumor progression in some circumstances. In this review, we summarize the body of work on CAFs, with a particular focus on the most recent discoveries about fibroblast heterogeneity, plasticity, and functions. We also highlight the commonalities of fibroblasts present across different cancer types, and in normal and inflammatory states. Finally, we present the latest advances regarding therapeutic strategies targeting CAFs that are undergoing preclinical and clinical evaluation.

The hepato-protective effect of eupatilin on an alcoholic liver disease model of rats

ABSTRACT Eupatilin is known to possess anti-apoptotic, anti-oxidative, and anti-inflammatory properties. We report here that eupatilin has a protective effect on the ethanol-induced injury in rats. Sprague–Dawley rats were divided into 6 groups: control, vehicle, silymarin, eupatilin 10 mg/kg, eupatilin 30 mg/kg, and eupatilin 100 mg/kg. Plasma levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were analyzed to determine the extent of liver damage. Total cholesterol (TC) and triglycerides (TG) were analyzed to determine the level of liver steatosis. Malondialdehyde level, superoxide dismutase (SOD) activity, and glutathione (GSH) level were analyzed to determine the extent of oxidative stress. Tumor necrosis factor (TNF)-α and interleukin (IL)-1β were quantified to verify the degree of inflammation. Based on our findings, chronic alcohol treatment significantly changed the serum indexes and liver indicators of the model rats, which were significantly improved by eupatilin treatment. Rats in the eupatilin-treatment group showed reduced levels of AST, ALT, TG, TC, TNF-α, and IL-1β, increased SOD activity and GSH levels, and improved overall physiology compared to the alcoholic liver disease model rats. H&E staining also verified the eupatilin-mediated improvement in liver injury. In conclusion, eupatilin inhibits alcohol-induced liver injury via its antioxidant and anti-inflammatory effects.

Nimbolide abrogates cerulein-induced chronic pancreatitis by modulating β-catenin/Smad in a sirtuin-dependent way

Chronic pancreatitis (CP) is one of the leading causes of mortality worldwide with no clinically approved therapeutic interventions. The present study was designed to investigate the protective effect of nimbolide (NB), an active constituent of neem tree (Azadirachta indica), by targeting β-catenin/Smad/SIRT1 in cerulein-induced CP model. The effects of NB was investigated on cerulein (50 μg/kg/hr*6 exposures /day, 3 days a week for 3 weeks) induced CP in mice. Amylase and lipase activity were measured and histopathological evaluation was performed. Collagen deposition in the pancreatic tissue was estimated by hydroxyproline assay, and collagen specific staining picrosirius red and Masson's trichrome. Cerulein-induced CP was significantly controlled by NB treatment, as shown by the downregulation of β-catenin/Smad signaling in a SIRT1 dependent manner. NB treatment significantly decreased α-SMA, MMP-2, collagen1a, fibronectin, TGF-β1, p-Smad-2/3 expression and extracellular matrix (ECM) deposition in pancreatic tissue. However, the protective effects of NB on cerulein-induced CP were undermined by nicotinamide (NMD) or splitomicin, sirtuin 1 (SIRT1) inhibitors treatment. NB treatment modulated protein expression by activating SIRT1 and decreasing the expression of β-catenin/Smad proteins in CP mice. However, the expression of SIRT1 in pancreatic tissue was elevated by NB treatment and it was decreased by NMD or splitomicin treatment. In summary, our results strongly suggest that NB exerted promising protective effects in cerulein-induced CP model by inhibiting β-catenin/Smad in a sirtuin-dependent manner, which could be attributed to its anti-inflammatory and antifibrotic effects. Our study suggests that NB could be an effective therapeutic intervention for the treatment of CP.

Antioxidants for Pancreatic Functions in Chronic Pancreatitis: A Double-blind Randomized Placebo-controlled Pilot Study

BACKGROUND

Antioxidants (AO) supplementation in chronic pancreatitis (CP) has been evaluated for pain. But it is not clear whether AO in CP have an effect on pancreatic functions and other clinical outcomes. We evaluated effect of AO on endocrine function in CP.

MATERIALS AND METHODS

Double-blind placebo (PL)-controlled randomized pilot study on 107 patients with CP assigned to receive daily combined AO or PL for 6 months. Primary outcome was: improvement in endocrine function (Homeostasis Model Assessment-Insulin Resistance). Secondary outcome measures were: improvement in C-peptide, Qualitative Insulin Sensitivity Check Index, exocrine pancreatic function (fecal elastase), surrogate markers of fibrosis (platelet-derived growth factor BB, transforming growth factor-β1, α-smooth muscle actin), quality of life (QOL), pain, nutritional status, markers of oxidative stress (OS), AO status, and inflammation.

RESULTS

There was an increase in levels of serum selenium (107.2±26.9 to 109.7±26.9 vs. 104.1±28.6 to 124.0±33.6 μg/L, P=0.022) and serum vitamin E [0.58 (range, 0.27-3.22) to 0.66 (range, 0.34-1.98) vs. 0.63 (range, 0.28-1.73) to 1.09 (range, 0.25-2.91) mg/dL, P=0.001] in the AO than the PL group. However, no significant differences were observed between groups in any of the primary or secondary outcome measures.

CONCLUSIONS

Supplementation with AO to patients with CP causes a sustained increase in blood levels of AO; however, it has no addition benefit over PL on endocrine and exocrine functions, markers of fibrosis, OS and inflammation, nutritional status, pain and QOL. Further larger studies with adequate sample size are required.

Eupatilin Ameliorates Cerulein-Induced Pancreatitis Via Inhibition of the Protein Kinase D1 Signaling Pathway In Vitro

OBJECTIVE

The aim of this study was to investigate the effects of eupatilin on protein kinase D1 (PKD1) and nuclear factor kappa B (NF-κB) signaling pathways in cerulein-induced in vitro pancreatitis.

METHODS

We used collagenase digestion to isolate pancreatic acinar cells from male C57BL/6 mice. In vitro acute pancreatitis was induced by treatment with a supramaximal dose of cerulein. Eupatilin was pretreated before stimulation with cerulein.

RESULTS

Eupatilin significantly reduced cerulein-induced amylase release in pancreatic acini. Eupatilin treatment downregulated cerulein-induced expression of interleukin (IL)-1β, IL-6, and CC chemokine ligands 2 and 5, but it upregulated expression of IL-4 and IL-10. We demonstrated that eupatilin pretreatment attenuated cerulein-induced necrosis in isolated pancreatic acinar cells. This effect of eupatilin was confirmed by lactic dehydrogenase assay, fluorescence-activated cell sorting analysis, and cytopathologic analysis. Eupatilin inhibited cerulein-induced activation of PKD1/NF-κB and the nuclear translocation of NF-κB.

CONCLUSIONS

Our data demonstrated that eupatilin is a potential therapeutic candidate for the treatment of pancreatitis through its ability to reduce cellular necrosis and inflammatory responses by inhibition of the PKD1/NF-κB signaling pathway.

Molecular Mechanism of Pancreatic Stellate Cells Activation in Chronic Pancreatitis and Pancreatic Cancer

Activated pancreatic stellate cells (PSCs) are the main effector cells in the process of fibrosis, a major pathological feature in pancreatic diseases that including chronic pancreatitis and pancreatic cancer. During tumorigenesis, quiescent PSCs change into an active myofibroblast-like phenotype which could create a favorable tumor microenvironment and facilitate cancer progression by increasing proliferation, invasiveness and inducing treatment resistance of pancreatic cancer cells. Many cellular signals are revealed contributing to the activation of PSCs, such as transforming growth factor-β, platelet derived growth factor, mitogen-activated protein kinase (MAPK), Smads, nuclear factor-κB (NF-κB) pathways and so on. Therefore, investigating the role of these factors and signaling pathways in PSCs activation will promote the development of PSCs-specific therapeutic strategies that may provide novel options for pancreatic cancer therapy. In this review, we systematically summarize the current knowledge about PSCs activation-associated stimulating factors and signaling pathways and hope to provide new strategies for the treatment of pancreatic diseases.

Cerulein-induced chronic pancreatitis in Swiss albino mice: An improved short-term model for pharmacological screening

There is a need for short-term, reliable and reproducible animal model of chronic pancreatitis (CP) in small animals like mice. This study was aimed to establish the 9 exposures of cerulein-induced CP in mice. Repeated intraperitoneal cerulein injections were performed at 6 consecutive doses (50 μg/kg)/day, 3 days a week for 3 weeks to induce chronic pancreatitis in Swiss albino mice. The severity of damage was assessed by biochemical assays and histopathology. The expression of pro-inflammatory cytokine and fibrotic proteins was assessed by IHC and western blotting. The cerulein treated mice showed significantly elevated plasma amylase (p < .0285) and lipase levels (p < .0022) and resulted in significantly increased pancreatic oxidative (p < .0022) and nitrosative (p < .0022) stress. The hydroxyproline levels were 3.06 fold increased in the cerulein treated mice. The expressions of fibrotic cytokine TGF-β1 by 1.8 folds and pro-inflammatory cytokines TNF-α by 2.3 fold, IL-6 by 2.2 fold and IL-1β by 3.7 fold were markedly increased in cerulein treated mice. The histological evaluations indicated increased inflammatory cells infiltration and deposition of collagen. Moreover, the expression of fibrotic markers such as α-SMA increased by 2.5 folds (p < .00014), collagen1a by 1.3 folds (p < .0258) and fibronectin by 3.5 folds (p < .00014) were significantly increased. Our study demonstrates the superiority of 9 exposures of cerulein-induced CP model in mice with the reduction of duration, cerulein exposure, more economical and mortality rate of mice over the available models. Therefore, our model may be suitable to evaluate the pharmacological effects of new drugs in chronic pancreatitis.

Novel and Experimental Therapies in Chronic Pancreatitis

Chronic pancreatitis (CP) is a progressive inflammatory disease of the pancreas. The currently available treatment of CP is aimed at controlling symptoms and managing complications. Unfortunately, no specific treatment is available to halt the progression of the disease process because the pathophysiological perturbations in CP are not well understood. In this review, we discuss various therapeutic targets and investigational agents acting on these targets. Among these, therapies modulating immune cells and those acting on pancreatic stellate cells appear promising and may translate into clinical benefit in near future. However, these experimental therapies are mostly in animal models and they do not recapitulate all aspects of human disease. Still they may be beneficial in developing effective therapeutic modalities to curb inflammation in chronic pancreatitis.

Characterization of Mouse Models of Early Pancreatic Lesions Induced by Alcohol and Chronic Pancreatitis

OBJECTIVE

We describe the first mouse model of pancreatic intraepithelial neoplasia (PanIN) lesions induced by alcohol in the presence and absence of chronic pancreatitis.

METHODS

Pdx1-Cre;LSL-K-ras mice were exposed to Lieber-DeCarli alcohol diet for 6 weeks with cerulein injections. The PanIN lesions and markers of fibrosis, inflammation, histone deacetylation, epithelial-to-mesenchymal transition (EMT), and cancer stemness were measured by immunohistochemistry and Western.

RESULTS

Exposure of Pdx1-Cre;LSL-K-ras mice to an alcohol diet significantly stimulated fibrosis and slightly but not significantly increased the level of PanIN lesions associated with an increase in tumor-promoting M2 macrophages. Importantly, the alcohol diet did not increase activation of stellate cells. Alcohol diet and cerulein injections resulted in synergistic and additive effects on PanIN lesion and M2 macrophage phenotype induction, respectively. Cerulein pancreatitis caused stellate cell activation, EMT, and cancer stemness in the pancreas. Pancreatitis caused histone deacetylation, which was promoted by the alcohol diet. Pancreatitis increased EMT and cancer stemness markers, which were not further affected by the alcohol diet.

CONCLUSIONS

The results suggest that alcohol has independent effects on promotion of PDAC associated with fibrosis formed through a stellate cell-independent mechanism and that it further promotes early PDAC and M2 macrophage induction in the context of chronic pancreatitis.

Vitamin D receptor-mediated stromal reprogramming suppresses pancreatitis and enhances pancreatic cancer therapy

The poor clinical outcome in pancreatic ductal adenocarcinoma (PDA) is attributed to intrinsic chemoresistance and a growth-permissive tumor microenvironment. Conversion of quiescent to activated pancreatic stellate cells (PSCs) drives the severe stromal reaction that characterizes PDA. Here, we reveal that the vitamin D receptor (VDR) is expressed in stroma from human pancreatic tumors and that treatment with the VDR ligand calcipotriol markedly reduced markers of inflammation and fibrosis in pancreatitis and human tumor stroma. We show that VDR acts as a master transcriptional regulator of PSCs to reprise the quiescent state, resulting in induced stromal remodeling, increased intratumoral gemcitabine, reduced tumor volume, and a 57% increase in survival compared to chemotherapy alone. This work describes a molecular strategy through which transcriptional reprogramming of tumor stroma enables chemotherapeutic response and suggests vitamin D priming as an adjunct in PDA therapy. PAPERFLICK:

Antioxidative phytoceuticals to ameliorate pancreatitis in animal models: An answer from nature

Despite enthusiastic efforts directed at elucidating critical underlying mechanisms towards the identification of novel therapeutic targets for severe acute pancreatitis (SAP), the disease remains without a specific therapy to be executed within the first hours to days after onset of symptoms. Although earlier management for SAP should aim to either treat organ failure or reduce infectious complications, the current standard of care for the general management of AP in the first hours to days after onset of symptoms include intravenous fluid replacement, nutritional changes, and the use of analgesics with a close monitoring of vital signs. Furthermore, repeated evaluation of severity is very important, as the condition is particularly unstable in the early stages. In cases where biliary pancreatitis is accompanied by acute cholangitis or in cases where biliary stasis is suspected, an early endoscopic retrograde cholangiopancreatography is recommended. However, practice guidelines regarding the treatment of pancreatitis are suboptimal. In chronic pancreatitis, conservative management strategies include lifestyle modifications and dietary changes followed by analgesics and pancreatic enzyme supplementation. Recently, attention has been focused on phytoceuticals or antioxidants as agents that could surpass the limitations associated with currently available therapies. Because oxidative stress has been shown to play an important role in the pathogenesis of pancreatitis, antioxidants alone or combined with conventional therapy may improve oxidative-stress-induced organ damage. Interest in phytoceuticals stems from their potential use as simple, accurate tools for pancreatitis prognostication that could replace older and more tedious methods. Therefore, the use of antioxidative nutrition or phytoceuticals may represent a new direction for clinical research in pancreatitis. In this review article, recent advances in the understanding of the pathogenesis of pancreatitis are discussed and the paradigm shift underway to develop phytoceuticals and antioxidants to treat it is introduced. Despite the promise of studies evaluating the effects of antioxidants/phytoceuticals in pancreatitis, translation to the clinic has thus far been disappointing. However, it is expected that continued research will provide solid evidence to justify the use of antioxidative phytoceuticals in the treatment of pancreatitis.

Nrf2-mediated mucoprotective and anti-inflammatory actions of Artemisia extracts led to attenuate stress related mucosal damages

The aim of this study was to compare biological actions between isopropanol and ethanol extracts of Artemisia including antioxidant, anti-inflammatory, and cytoprotective actions. Antioxidant activities were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and confocal microscopy on lipopolysaccharide-induced RGM1 cells, cytoprotection effects evaluated by detecting heme oxygenase-1 (HO-1), Nf-E2 related factor2 (Nrf2) and heat shock protein 70 (HSP70), and anti-inflammatory effects investigated by measuring inflammatory mediators. Water immersion restraint stress was imposed to provoke stress related mucosal damages (SRMD) in rats. Isopropanol extracts of Artemisia showed the higher DPPH radical scavenging activity and lesser LPS-induced reactive oxygen species productions and increased HO-1 expression through increased nuclear translocation of Nrf2 transcription factor compared to ethanol extracts. The increased expression of HSP70 and decreased expression of endothelin-1 were only increased with isopropanol extracts. A concentration-dependent inhibition of LPS-induced COX-2 and iNOS even at a rather lower concentration than ethanol extract was achieved with isopropanol extracts. Cytokine protein array revealed Artemisia extracts significantly attenuated the levels of CXCL-1, CXCL-16, and MCP-1. These orchestrated actions led to significant rescue from SRMD. Conclusively, Artemisia extracts imposed significant antioxidant and anti-inflammatory activity against SRMD and isopropanol extracts were superior to ethanol extracts in these beneficiary actions of Artemisia.

Short-term Intervention to Revert Premalignant Lesions as Strategy to Prevent Gastrointestinal Cancers

"Prevention might be better than treatment in cancer treatment" is brief conclusion drawn from war on cancer through National Cancer Act of 1971 by U.S. President Richard Nixon. However, the clinical practice of chemoprevention is still in its infancy in spite of a wealth of data showing its effectiveness in experimental animals as well as in vitro mechanism research. Recent advances in either high throughput analysis including cancer genomes and tailored medicine or molecular targeted therapeutics, preventive strategies also should be changes as previous preventive strategies including phytoceuticals, life-style modification, and some empirical agents. Furthermore, molecular targeted therapeutics achieved high goal of effectiveness under the concept of therapeutic or preventive "synthetic lethality", of which extended application can be included within the scope of chemoprevention. Here, we will summarize several recent advances in chemopreventive strategy objected to justify optimism that chemoprevention will be an effective approach for the control of human cancer. siTRP (short-term intervention to revert premalignancy) strategy will be introduced for cancers in gastroenterology.

Potential role of NADPH oxidase in pathogenesis of pancreatitis

Studies have demonstrated that reactive oxygen species (ROS) are closely related to inflammatory disorders. Nicotinamide adenine dinucleotide phosphate oxidase (NOX), originally found in phagocytes, is the main source of ROS in nonphagocytic cells. Besides directly producing the detrimental highly reactive ROS to act on biomolecules (lipids, proteins, and nucleic acids), NOX can also activate multiple signal transduction pathways, which regulate cell growth, proliferation, differentiation and apoptosis by producing ROS. Recently, research on pancreatic NOX is no longer limited to inflammatory cells, but extends to the aspect of pancreatic acinar cells and pancreatic stellate cells, which are considered to be potentially associated with pancreatitis. In this review, we summarize the literature on NOX protein structure, activation, function and its role in the pathogenesis of pancreatitis.

Reappraisal of xenobiotic-induced, oxidative stress-mediated cellular injury in chronic pancreatitis: A systematic review

AIM: To reappraise the hypothesis of xenobiotic induced, cytochrome P450-mediated, micronutrient-deficient oxidative injury in chronic pancreatitis.

METHODS: Individual searches of the Medline and Embase databases were conducted for each component of the theory of oxidative-stress mediated cellular injury for the period from 1^st January 1990 to 31^st December 2012 using appropriate medical subject headings. Boolean operators were used. The individual components were drawn from a recent update on theory of oxidative stress-mediated cellular injury in chronic pancreatitis.

RESULTS: In relation to the association between exposure to volatile hydrocarbons and chronic pancreatitis the studies fail to adequately control for alcohol intake. Cytochrome P450 (CYP) induction occurs as a diffuse hepatic and extra-hepatic response to xenobiotic exposure rather than an acinar cell-specific process. GSH depletion is not consistently confirmed. There is good evidence of superoxide dismutase depletion in acute phases of injury but less to support a chronic intra-acinar depletion. Although the liver is the principal site of CYP induction there is no evidence to suggest that oxidative by-products are carried in bile and reflux into the pancreatic duct to cause injury.

CONCLUSION: Pancreatic acinar cell injury due to short-lived oxygen free radicals (generated by injury mediated by prematurely activated intra-acinar trypsin) is an important mechanism of cell damage in chronic pancreatitis. However, in contemporary paradigms of chronic pancreatitis this should be seen as one of a series of cell-injury mechanisms rather than a sole mediator.

Decreased serum paraoxonase activity in patients with chronic pancreatitis

BACKGROUND

Recent evidences suggest that oxidative stress is involved in the mechanism of chronic pancreatitis (CP). Paraoxonase 1 (PON1) plays an important role as an endogenous free-radical scavenging molecule. The aim of our study is to investigate whether serum PON1 activity is associated with the presence of CP.

METHODS

A total of 186 patients with alcoholic CP and 132 healthy subjects were enrolled in this study. Serum PON1 activity was measured using paraoxon as a substrate.

RESULTS

Serum PON1 activity was significantly decreased in CP patients compared with healthy subjects. Multivariable logistic regression analysis revealed that serum PON1 activity was a determinant of the presence of CP (OR = 0.992, 95% CI = 0.987-0.998; P = 0.006).

CONCLUSIONS

Decreased serum PON1 activity may be considered as a predicting marker of the presence of CP.

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.

Protective effects of edaravone on experimental chronic pancreatitis induced by dibutyltin dichloride in rats

BACKGROUND/AIMS

To investigate the effects of edaravone, a potent free radical scavenger, on dibutyltin dichloride (DBTC)-induced chronic pancreatitis (CP) and pancreatic fibrosis.

METHODS

Male Sprague-Dawley rats were randomly divided into four groups (n = 16 each): control, DBTC, DBTC + edaravone, and control + edaravone. Edaravone or normal saline at a daily dose of 6 mg/kg body weight was given intraperitoneally from day 5 to day 28 after DBTC administration. On days 14 and 28, the rats were evaluated morphologically and biochemically. The expression of cytokines in pancreas TGF-β, IL-6 and TNF<alpha> was detected using RT-PCR. The activation of nuclear factor (NF)-κB in pancreatic tissue was evaluated by immunostaining and western-blot for NF-κB p65. α-smooth muscle actin (α-SMA) expression was also evaluated by immunostaining and western-blot to investigate the activation of pancreatic stellate cells (PSCs).

RESULT

Edaravone treatment improved the rats' body weight (p < 0.01) and feed intake levels (p < 0.05), improved the histological scores and alleviated the fibrosis of pancreas samples (p < 0.05), as well as markedly increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) concentrations in pancreatic tissue (p < 0.01 for both). The expression of cytokines TGF-β, IL-6 and TNF<alpha> in pancreas of DBTC group was also down-regulated by edaravone after treatment. Edaravone inhibited the activation of NF-κB and PSCs and exhibited protective effects on pancreatic tissue damage in CP.

CONCLUSIONS

This antioxidant may be a promising therapeutic intervention for human CP.

Involvement of inflammatory factors in pancreatic carcinogenesis and preventive effects of anti-inflammatory agents

Chronic inflammation is known to be a risk for many cancers, including pancreatic cancer. Heavy alcohol drinking and cigarette smoking are major causes of pancreatitis, and epidemiological studies have shown that smoking and chronic pancreatitis are risk factors for pancreatic cancer. Meanwhile, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) are elevated in pancreatitis and pancreatic cancer tissues in humans and in animal models. Selective inhibitors of iNOS and COX-2 suppress pancreatic cancer development in a chemical carcinogenesis model of hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). In addition, hyperlipidemia, obesity, and type II diabetes are also suggested to be associated with chronic inflammation in the pancreas and involved in pancreatic cancer development. We have shown that a high-fat diet increased pancreatic cancer development in BOP-treated hamsters, along with aggravation of hyperlipidemia, severe fatty infiltration, and increased expression of adipokines and inflammatory factors in the pancreas. Of note, fatty pancreas has been observed in obese and/or diabetic cases in humans. Preventive effects of anti-hyperlipidemic/anti-diabetic agents on pancreatic cancer have also been shown in humans and animals. Taking this evidence into consideration, modulation of inflammatory factors by anti-inflammatory agents will provide useful data for prevention of pancreatic cancer.

The effect of sulindac, a non-steroidal anti-inflammatory drug, attenuates inflammation and fibrosis in a mouse model of chronic pancreatitis

BACKGROUND

Chronic pancreatitis is characterized by progressive fibrosis, pain and loss of exocrine and endocrine functions. The long-standing chronic pancreatitis and its associated pancreatic fibrosis are the most common pathogenic events involved in human pancreatic carcinogenesis, but the therapeutic strategies to chronic pancreatitis and the chemoprevention of pancreatic carcinogenesis are very limited.

METHODS

We investigated the effect of sulindac, a non-steroidal anti-inflammatory drug (NSAID), on inhibition of chronic pancreatitis in a caerulein induced chronic pancreatitis mouse model.

RESULTS

Sulindac significantly reduced the severity of chronic pancreatitis including the extent of acini loss, inflammatory cell infiltration and stromal fibrosis. The protein expression of phosphorylation of MEK/ERK was inhibited in the chronic pancreatic tissues by sulindac treatment as measured by Western blot assay. The levels of inflammatory cytokines including TNF-α and MCP-1 were also significantly decreased with sulindac treatment, as well as the expression of TGF-β, PDGF-β, SHH and Gli in the chronic pancreatic tissue detected by qPCR assay and confirmed by western blot assay. The activation of pancreatic satellet cells was also inhibited by sulindac as measured by the activity of α-smooth muscle actin (α-SMA) in the pancreatic tissue of chronic pancreatitis.

CONCLUSIONS

Sulindac is a promising reagent for the treatment of chronic pancreatitis via inhibition of inflammatory cell infiltration and stromal fibrosis, the inhibitory effect of sulindac on chronic pancreatitis may through targeting the activation ERK/MAPK signaling pathway.

Early proteome analysis of rat pancreatic acinar AR42J cells treated with taurolithocholic acid 3-sulfate

BACKGROUND

Bile acids are the initiating factors of biliary acute pancreatitis. Bile acids can induce the activation of intracellular zymogen, thus leading injury in pancreatic acinar cells. Pathological zymogen activation in pancreatic acinar cells is a common feature of all types of acute pancreatitis. The proteins expressed in pancreatic acinar cells during the activation of zymogen may determine the severity of acute pancreatitis. The present study aims to determine the differentially expressed proteins in taurolithocholic acid 3-sulfate-stimulated pancreatic acinar cells as an in vitro model for acute pancreatitis.

METHODS

Rat pancreatic acinar AR42J cells were treated with taurolithocholic acid 3-sulfate for 20 min. Laser confocal scanning microscopy and flow cytometry were used to detect activated trypsinogen in pancreatic acinar AR42J cells. After the determination of trypsinogen activation, proteome analysis was performed to identify the proteins differentially expressed in taurolithocholic acid 3-sulfate-treated cells and non-treated cells.

RESULTS

After treatment with taurolithocholic acid 3-sulfate for 20 min, the activation of trypsinogen in AR42J cells was concurrent with changes in the protein expression profile. Thirty-nine differentially expressed proteins were detected; among these, 23 proteins were up-regulated and 16 proteins were down-regulated. KEGG analysis indicated that these proteins are involved in cellular metabolic pathways, cellular defensive mechanisms, intracellular calcium regulation and cytoskeletal changes.

CONCLUSION

The expression of proteins in the pancreatic acinar cell changes at the early stage of biliary acute pancreatitis. These differentially expressed proteins will provide valuable information to understand the pathophysiologic mechanism biliary acute pancreatitis and may be useful for prognostic indices of acute pancreatitis.

L-cysteine administration attenuates pancreatic fibrosis induced by TNBS in rats by inhibiting the activation of pancreatic stellate cell

BACKGROUND AND AIMS

Recent studies have shown that activated pancreatic stellate cells (PSCs) play a major role in pancreatic fibrogenesis. We aimed to study the effect of L-cysteine administration on fibrosis in chronic pancreatitis (CP) induced by trinitrobenzene sulfonic acid (TNBS) in rats and on the function of cultured PSCs.

METHODS

CP was induced by TNBS infusion into rat pancreatic ducts. L-cysteine was administrated for the duration of the experiment. Histological analysis and the contents of hydroxyproline were used to evaluate pancreatic damage and fibrosis. Immunohistochemical analysis of α-SMA in the pancreas was performed to detect the activation of PSCs in vivo. The collagen deposition related proteins and cytokines were determined by western blot analysis. DNA synthesis of cultured PSCs was evaluated by BrdU incorporation. We also evaluated the effect of L-cysteine on the cell cycle and cell activation by flow cytometry and immunocytochemistry. The expression of PDGFRβ, TGFβRII, collagen 1α1 and α-SMA of PSCs treated with different concentrations of L-cysteine was determined by western blot. Parameters of oxidant stress were evaluated in vitro and in vivo. Nrf2, NQO1, HO-1, IL-1β expression were evaluated in pancreas tissues by qRT-PCR.

RESULTS

The inhibition of pancreatic fibrosis by L-cysteine was confirmed by histological observation and hydroxyproline assay. α-SMA, TIMP1, IL-1β and TGF-β1 production decreased compared with the untreated group along with an increase in MMP2 production. L-cysteine suppressed the proliferation and extracellular matrix production of PSCs through down-regulating of PDGFRβ and TGFβRII. Concentrations of MDA+4-HNE were decreased by L-cysteine administration along with an increase in GSH levels both in tissues and cells. In addition, L-cysteine increased the mRNA expression of Nrf2, NQO1 and HO-1 and reduced the expression of IL-1β in L-cysteine treated group when compared with control group.

CONCLUSION

L-cysteine treatment attenuated pancreatic fibrosis in chronic pancreatitis in rats.

Comparison of antioxidative and antifibrotic effects of α-tocopherol with those of tocotrienol-rich fraction in a rat model of chronic pancreatitis

OBJECTIVES

The α-tocopherol and tocotrienol-rich fraction (TRF) are considered effective antioxidants. This study aimed to compare the antioxidative and antifibrotic effects of α-tocopherol and TFR in dibutylin dichloride (DBTC)-induced chronic pancreatitis (CP) rats.

METHODS

Oral administration of α-tocopherol and TFR (both 800 mg/kg per day) started the next day after DBTC (8 mg/kg) infusion into the tail vein for 4 weeks. Histological examination, Sirius red staining, and measurement of the contents of hydroxyproline and malondialdehyde of the pancreas were performed to evaluate pancreatic damage and fibrosis. Immunohistochemical analysis of α-smooth muscle actin and real-time reverse transcription polymerase chain reaction for transforming growth factor-β1 (TGF-β1) and collagen-α1(I) were performed to evaluate the activation of pancreatic stellate cells and the mRNA levels of fibrosis-related genes, respectively.

RESULTS

Both α-tocopherol and TRF reduced oxidative stress, ameliorated inflammation and fibrosis, and down-regulated the mRNA expression of TGF-β1 and collagen-α1(I) in DBTC-induced CP. The TRF was superior to α-tocopherol in alleviating inflammation and fibrosis and down-regulating TGF-β1 mRNA expression.

CONCLUSIONS

Oral administration of α-tocopherol and TRF improves pancreatic inflammation and fibrosis in DBTC-induced CP rats, with TRF being more effective than α-tocopherol. Therefore, TRF may be a novel option for alleviating inflammation and, particularly, the fibrotic process in CP.

Inhibition of chronic pancreatitis and pancreatic intraepithelial neoplasia (PanIN) by capsaicin in LSL-KrasG12D/Pdx1-Cre mice

Capsaicin is a major biologically active ingredient of chili peppers. Extensive studies indicate that capsaicin is a cancer-suppressing agent via blocking the activities of several signal transduction pathways including nuclear factor-kappaB, activator protein-1 and signal transducer and activator of transcription 3. However, there is little study on the effect of capsaicin on pancreatic carcinogenesis. In the present study, the effect of capsaicin on pancreatitis and pancreatic intraepithelial neoplasia (PanIN) was determined in a mutant Kras-driven and caerulein-induced pancreatitis-associated carcinogenesis in LSL-Kras(G12D)/Pdx1-Cre mice. Forty-five LSL-Kras(G12D)/Pdx1-Cre mice and 10 wild-type mice were subjected to one dose of caerulein (250 μg/kg body wt, intraperitoneally) at age 4 weeks to induce and synchronize the development of chronic pancreatitis and PanIN lesions. One week after caerulein induction, animals were randomly distributed into three groups and fed with either AIN-76A diet, AIN-76A diet containing 10 p.p.m. capsaicin or 20 p.p.m. capsaicin for a total of 8 weeks. The results showed that capsaicin significantly reduced the severity of chronic pancreatitis, as determined by evaluating the loss of acini, inflammatory cell infiltration and stromal fibrosis. PanIN formation was frequently observed in the LSL-Kras(G12D)/Pdx1-Cre mice. The progression of PanIN-1 to high-grade PanIN-2 and -3 were significantly inhibited by capsaicin. Further immunochemical studies revealed that treatment with 10 and 20 p.p.m. capsaicin significantly reduced proliferating cell nuclear antigen-labeled cell proliferation and suppressed phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun as well blocked Hedgehog/GLI pathway activation. These results indicate that capsaicin could be a promising agent for the chemoprevention of pancreatic carcinogenesis, possibly via inhibiting pancreatitis and mutant Kras-led ERK activation.

COX-2 is not required for the development of murine chronic pancreatitis

Chronic pancreatitis is a severe inflammation of the pancreas associated with destruction of the parenchyma, fibrosis, and persistent abdominal pain. Cyclooxygenase-2 (COX-2) and COX-2-derived prostaglandins, key mediators of the inflammatory response, are elevated in patients with chronic pancreatitis. Previous studies investigated COX-2 as a therapeutic target. These reports showed a reduced pathology in COX-2-deficient mice with a better outcome. Here we compared the role of COX-2 in acute and chronic pancreatic inflammation using the same COX-2(-/-) mouse model of cerulein-induced pancreatitis. In a setting of acute pancreatitis, juvenile COX-2(-/-) mice exhibited a reduced histopathological score compared with wild-type littermates; on the contrary, adult mice did not show any difference in the development of the disease. Similarly, in a setting of chronic pancreatitis induced over a period of 4 wk, adult mice of the two strains showed comparable histological score and collagen deposition. However, the abundance of mRNAs coding for profibrotic genes, such as collagen, α-smooth muscle actin, and transforming growth factor-β was consistently lower in COX-2(-/-) mice. In addition, comparable histological scores and collagen deposition were observed in wild-type mice treated with a COX-2 inhibitor. We conclude that, in contrast to what was observed in the rat pancreatitis models, COX-2 has a limited and age-dependent effect on inflammatory processes in the mouse pancreas. These results suggest that COX-2 modulates the inflammatory process during the development of pancreatitis in a species-specific manner. Thus the pathophysiological roles of COX-2 and its therapeutic implications in patients with pancreatitis should be reexamined.

α-Tocopherol treatment ameliorates chronic pancreatitis in an experimental rat model induced by trinitrobenzene sulfonic acid

OBJECTIVE

To investigate the effects of α-tocopherol on pancreatic fibrosis and survival in rats with experimental chronic pancreatitis induced by trinitrobenzene sulfonic acid (TNBS).

METHODS

Chronic pancreatitis was induced in male Sprague-Dawley rats by infusion of TNBS into the pancreatic duct. α-Tocopherol (300, 600 or 900 mg/kg) was orally administered to rats with experimental pancreatitis (treatment group) daily for 4 weeks. The relative pancreatic weight, pancreatic pseudocyst and death rate were observed. Paraffin-embedded tissue samples were sliced, stained by hematoxylin-eosin and histopathologically examined.

RESULTS

α-Tocopherol administration significantly ameliorated the pancreatic weight loss induced by TNBS in chronic pancreatitis rats compared to the control group. There were pancreatic pseudocysts in 69% of the α-tocopherol group, and in 100% of the control group. α-Tocopherol administration led to a significant increase of the survival rate. The histopathologic scores were higher in the control group than in the α-tocopherol group. Subgroup analysis of histopathologic scores revealed that a high dose of α-tocopherol results in less pancreatic injuries.

CONCLUSION

α-Tocopherol treatment elevates survival rate, extenuates fibrosis and increases relative pancreatic weight in the chronic pancreatitis model. α-Tocopherol therapy in chronic pancreatitis is now required to confirm these findings and establish the role of this treatment in the management of this disabling condition. and IAP.

Chronic pancreatitis: potential future interventions

Chronic pancreatitis is a common disorder of which the underlying pathogenic mechanisms still are incompletely understood. In the last decade, increasing evidence has shown that activated pancreatic stellate cells play a key role in the fibrosis development associated with chronic pancreatitis as well as pancreatic cancer. During pancreatic injury or inflammation, quiescent stellate cells undergo a phenotypic transformation, characterized by smooth muscle alpha-actin expression and increased synthesis of extracellular matrix proteins. Hitherto, specific therapies to prevent or reverse pancreatic fibrosis are unavailable. This review addresses current insights into pathological mechanisms underlying chronic pancreatitis and their applicability as concerns the development of potential future therapeutic approaches.

High-dose naproxen aggravates pancreatic fibrosis in a rat model of chronic pancreatitis

OBJECTIVES

: Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed for the treatment of pain in chronic pancreatitis (CP). This study aimed to investigate the effect of NSAIDs on the inflammation and fibrosis progression in trinitrobenzene sulfonic acid-induced CP rats.

METHODS

Chronic pancreatitis was induced by trinitrobenzene sulfonic acid infusion into rat pancreatic ducts. Naproxen treatment (20 and 40 mg/kg per os [PO] and intraperitoneally) started 2 weeks after the induction of CP for 3 weeks. Histological analysis of the pancreas, Van Gieson staining, and contents of hydroxyproline were used to evaluate pancreatic damage and fibrosis. Furthermore, the effect of naproxen on nociceptive reflective behaviors and serum tumor necrosis factor alpha concentration were studied, and immunohistochemical analysis of alpha-smooth muscle actin in the pancreas was performed.

RESULTS

Pancreatic collagen content and alpha-smooth muscle actin expression were higher in the CP group treated with high-dose (40 mg/kg PO) naproxen (P < 0.05). High-dose naproxen administered orally aggravated pancreatic fibrosis and inflammation (P < 0.05). Instead of playing an analgesic role, high-dose naproxen decreased the thermal withdrawal latencies in CP rats (P < 0.05).

CONCLUSIONS

High-dose naproxen treatment (40 mg/kg PO) aggravated pancreatic fibrosis in CP rats and played an algogenic role that suggests the potential risk of long-term use of NSAIDs as analgesic in clinical practice with CP.

Protection against chronic pancreatitis and pancreatic fibrosis in mice overexpressing pancreatic secretory trypsin inhibitor

OBJECTIVES

Mutations in the gene encoding for pancreatic secretory trypsin inhibitor (PSTI) can contribute to chronic pancreatitis. In the current study, we tested whether overexpression of PSTI-I in mice protects against chronic pancreatitis and pancreatic fibrosis.

METHODS

Rat PSTI-I expression was targeted to pancreatic acinar cells in transgenic mice. Chronic pancreatitis was achieved by intraperitoneal injection of cerulein for 10 weeks. Pancreatitis severity was assessed by histological grading of inflammatory infiltrate, atrophy, and fibrosis; quantitation of myeloperoxidase (MPO) activity; quantitative morphometric analysis of collagen content; and measurements of type I collagen, fibronectin, and transforming growth factor beta mRNA expression.

RESULTS

Cerulein administration to nontransgenic mice produced histological evidence of inflammatory infiltrate, glandular atrophy, and parenchymal fibrosis and increased collagen production, MPO activity, and collagen I and fibronectin mRNA levels. In cerulein-treated PSTI transgenic mice, there were significant reductions in inflammatory infiltrate, MPO activity, fibrosis, and collagen I and fibronectin mRNA levels. Transgenic mice treated with cerulein had significantly less collagen than nontransgenic mice.

CONCLUSIONS

The severity of chronic pancreatitis and pancreatic fibrosis is significantly reduced in mice expressing rat PSTI-I. We propose that pancreatic trypsin inhibitors play a protective role in the pancreatic response to repeated injurious events.

Signal transduction in pancreatic stellate cells

Pancreatic fibrosis is a characteristic feature of chronic pancreatitis and of desmoplastic reaction associated with pancreatic cancer. For over a decade, there has been accumulating evidence that activated pancreatic stellate cells (PSCs) play a pivotal role in the development of pancreatic fibrosis in these pathological settings. In response to pancreatic injury or inflammation, quiescent PSCs undergo morphological and functional changes to become myofibroblast-like cells, which express alpha-smooth muscle actin (alpha-SMA). Activated PSCs actively proliferate, migrate, produce extracellular matrix (ECM) components, such as type I collagen, and express cytokines and chemokines. In addition, PSCs might play roles in local immune functions and angiogenesis in the pancreas. Following the initiation of activation, if the inflammation and injury are sustained or repeated, PSCs activation is perpetuated, leading to the development of pancreatic fibrosis. From this point of view, pancreatic fibrosis can be defined as pathological changes of ECM composition in the pancreas both in quantity and quality, resulting from perpetuated activation of PSCs. Because the activation and cell functions in PSCs are regulated by the dynamic but coordinated activation of intracellular signaling pathways, identification of signaling molecules that play a crucial role in PSCs activation is important for the development of anti-fibrosis therapy. Recent studies have identified key mediators of stimulatory and inhibitory signals. Signaling molecules, such as peroxisome proliferator-activated receptor-gamma (PPAR-gamma), Rho/Rho kinase, nuclear factor-kappaB (NF-kappaB), mitogen-activated protein (MAP) kinases, phosphatidylinositol 3 kinase (PI3K), Sma- and Mad-related proteins, and reactive oxygen species (ROS) might be candidates for the development of anti-fibrosis therapy targeting PSCs.

Chemopreventive effects of the standardized extract (DA-9601) of Artemisia asiatica on azoxymethane-initiated and dextran sulfate sodium-promoted mouse colon carcinogenesis

Dextran sulfate sodium (DSS) administration has been reported to cause inflammation in mouse colonic mucosa, which promotes colon carcinogenesis. When male ICR mice were treated with a single intraperitoneal dose (10 mg/kg body weight) of azoxymethane (AOM) followed by 2.5% DSS in drinking water for 7 consecutive days, all developed tumors at the 16th wk, mostly in the distal colon. Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were markedly upregulated in the AOM-initiated and DSS-promoted colon tumors. The DNA binding activity of nuclear factor-kappaB (NF-kappa B) was also elevated in the colon tumors. In this study, we examined the chemopreventive effects of the standardized extract (DA-9601) of Artemisia asiatica that has been used in the traditional herbal medicine for the treatment of inflammatory disorders. Mice fed the chow diet containing 10% DA-9601 for 15 wk following DSS treatment displayed the significantly lower multiplicity of colon tumors. DA-9601 treatment suppressed the expression of COX-2 and iNOS as well as NF-kappa B DNA binding in the colonic tissues. It also downregulated the phosphorylation of extracellular, signal-regulated protein kinase and p38 mitogen-activated protein kinase that are upstream of NF-kappa B. Furthermore, DA-9601 reduced expression of beta-catenin in colonic mucosa of mice challenged with AOM plus DSS.

Role of oxidative stress in pancreatic inflammation

Reactive oxygen and reactive nitrogen species (ROS/RNS) have been implicated in the pathogenesis of acute and chronic pancreatitis. Clinical and basic science studies have indicated that ROS/RNS formation processes are intimately linked to the development of the inflammatory disorders. The detrimental effects of highly reactive ROS/RNS are mediated by their direct actions on biomolecules (lipids, proteins, and nucleic acids) and activation of proinflammatory signal cascades, which subsequently lead to activation of immune responses. The present article summarizes the possible sources of ROS/RNS formation and the detailed signaling cascades implicated in the pathogenesis of pancreatic inflammation, as observed in acute and chronic pancreatitis. A therapeutic ROS/RNS-scavenging strategy has been advocated for decades; however, clinical studies examining such approaches have been inconsistent in their results. Emerging evidence indicates that pancreatitis-inducing ROS/RNS generation may be attenuated by targeting ROS/RNS-generating enzymes and upstream mediators.

Protective effect of salvianolic acid B on chronic pancreatitis induced by trinitrobenzene sulfonic acid solution in rats

OBJECTIVES

To investigate the effects of salvianolic acid B (Sal-B) on pancreatic damage in experimental chronic pancreatitis.

METHODS

Chronic pancreatitis was induced by infusion of trinitrobenzene sulfonic acid into the pancreatic duct in male Sprague-Dawley rats. From the beginning of 5 weeks, the rats in group 2 were treated with Sal-B by gavage for 8 weeks. Salvianolic acid B was given at a daily dose of 10 mg/kg body weight. At the end of 12 weeks, the levels of serum biochemical indexes were measured on an automatic biochemical analyzer; serum hyaluronic acid and laminin levels were determined by radioimmunoassay; pancreatic tissue malondialdehyde (MDA) was analyzed, and the degree of pancreatic damage was determined.

RESULTS

The level of serum biochemical indexes were similar in all groups (P > 0.05 for all). Salvianolic acid B treatment did not obviously reduce hyaluronic acid and laminin concentration in blood (P > 0.05). Salvianolic acid B treatment decreased MDA concentration in pancreatic tissue (P < 0.01). Salvianolic acid B clearly improved pancreatic histological findings and prevented the activation of pancreatic stellate cells.

CONCLUSIONS

Sal-B treatment decreased MDA concentration in pancreatic tissue, attenuated morphological pancreatic damage, and prevented the activation of pancreatic stellate cells in experimental chronic pancreatitis.

Reduction of inflammation and chronic tissue damage by omega-3 fatty acids in fat-1 transgenic mice with pancreatitis

Pancreatitis is a severe debilitating disease with high morbidity and mortality. Treatment is mostly supportive, and until now there are no clinically useful strategies for anti-inflammatory therapy. Although omega-3 polyunsaturated fatty acids (n-3 PUFA) are known to have anti-inflammatory effects, the utility of these fatty acids in the alleviation of pancreatitis remained to be investigated. The aim of this study was to examine the effect of n-3 PUFA on both acute and chronic pancreatitis in a well-controlled experimental system. We used the fat-1 transgenic mouse model, characterized by endogenously increased tissue levels of n-3 PUFA, and their wild-type littermates to examine the effect of n-3 PUFA on both acute and chronic cerulein-induced pancreatitis. Disease activity and inflammatory status were assessed by both histology and molecular methods. In acute pancreatitis, fat-1 mice showed a trend towards decreased necrosis and significantly reduced levels of plasma IL-6 levels as well as reduced neutrophil infiltration in the lung. In chronic pancreatitis there was less pancreatic fibrosis and collagen content accompanied by decreased pancreatic stellate cell activation in the fat-1 animals with increased n-3 PUFA tissue levels as compared to wild-type littermates with high levels of omega-6 (n-6) PUFA in their tissues. Our data provide evidence for a reduction of systemic inflammation in acute pancreatitis and of tissue fibrosis in chronic pancreatitis by increasing the tissue content of omega-3 polyunsaturated fatty acids. These results suggest a beneficial potential for n-3 PUFA supplementation in acute and particularly chronic pancreatitis.

Nitric oxide as a target of complementary and alternative medicines to prevent and treat inflammation and cancer

Nitric oxide (NO) and associated reactive nitrogen species (RNS) are involved in many physiological functions. There has been an ongoing debate to whether RNS can inhibit or perpetuate chronic inflammation and associated carcinogenesis. Although the final outcome depends on the genetic make-up of its target, the surrounding microenvironment, the activity and localization of nitric oxide synthase (NOS) isoforms, and overall levels of NO/RNS, evidence is accumulating that in general, RNS drive inflammation and cancers associated with inflammation. To this end, many complementary and alternative medicines (CAMs) that work in chemoprevention associated with chronic inflammation, are inhibitors of excessive NO observed in inflammatory conditions. Here, we review recent literature outlining a role of NO/RNS in chronic inflammation and cancer, and point toward NO as one of several targets for the success of CAMs in treating chronic inflammation and cancer associated with this inflammation.

Protective effect of inducible nitric oxide synthase inhibitor on pancreas transplantation in rats

AIM

To investigate the effect of inducible nitric oxide synthase inhibitor, aminoguanidine, on pancreas transplantation in rats.

METHODS

A model of pancreas transplantation was established in rats. Streptozotocin-induced diabetic male Wistar rats were randomly assigned to sham-operation control group (n = 6), transplant control group (n = 6), and aminoguanidine (AG) treatment group (n = 18). In the AG group, aminoguanidine was added to intravascular infusion as the onset of reperfusion at the dose of 60 mg/kg, 80 mg/kg, 100 mg/kg body weight, respectively. Serum nitric oxide (NO) level, blood sugar and amylase activity were detected. Nitric oxide synthase (NOS) test kit was used to detect the pancreas cNOS and inducible NOS (iNOS) activity. Pancreas sections stained with HE and immunohistochemistry were evaluated under a light microscope.

RESULTS

As compared with the transplant control group, the serum NO level and amylase activity decreased obviously and the evidence for pancreas injury was much less in the AG group. The AG (80 mg/kg body weight) group showed the most significant difference in NO and amylase (NO: 66.0 +/- 16.6 vs 192.3 +/- 60.0, P < 0.01 and amylase: 1426 +/- 177 vs 4477 +/- 630, P < 0.01). The expression and activity of tissue iNOS, and blood sugar in the AG (80 mg/kg body weight) group were much lower than those in the transplant control group (iNOS: 2.01 +/- 0.23 vs 26.59 +/- 5.78, P < 0.01 and blood sugar: 14.2 +/- 0.9 vs 16.8 +/- 1.1, P < 0.01).

CONCLUSION

Selective iNOS inhibitor, aminoguanidine as a free radical, has a protective effect on pancreas transplantation in rats by inhibiting NO and reducing its toxicity.

Crucial role of fibrogenesis in pancreatic diseases

Chronic pancreatitis and pancreatic cancer are characterised by a progressive fibrosis. Accumulation of extracellular matrix not only accompanies both diseases but is directly involved in their progression, suggesting inhibition of fibrogenesis as a potential therapeutic strategy. Pancreatic stellate cells (PSC) are the main extracellular matrix-producing cell type in the diseased pancreas. In response to pro-fibrogenic mediators including cytokines and ethanol metabolites, PSC undergo phenotypic changes termed activation, resulting in the exhibition of a myofibroblast-like phenotype. In the perpetuation of PSC activation, autocrine loops of mediators such as transforming growth factor beta play an important role. Most recently signal transduction pathways in PSC that are associated with the process of activation were characterised, facilitating identification of potential intracellular targets for an anti-fibrotic therapy. While some putative inhibitors of fibrogenesis have been tested in animal models of pancreatic fibrosis for their in vivo efficiency, clinical studies still remain to be performed.

Pancreatic stellate cells: new target in the treatment of chronic pancreatitis

Chronic pancreatitis (CP) is characterized by progressive fibrosis, pain and/or loss of exocrine and endocrine functions. Recent in vitro and in vivo experiments have proven objectively the role of activated pancreatic stellate cells (PSC) in fibrogenesis in CP. Molecular mediators shown to regulate the pathogenesis include transforming growth factor beta (TGF-beta), platelet-derived growth factor (PDGF), and pro-inflammatory cytokines such as IL-1, IL-6 and TNF-alpha. Furthermore, molecular pathways involving mitogen-activated protein kinases (MAPK), phosphatidyl inositol 3-kinase (PI3K), Ras superfamily G proteins, serine threonine protein kinase Raf-1 and peroxisome proliferator activated receptor gamma (PPAR-gamma) have been elucidated. Understanding of the pathogenesis has led to identification of novel molecular targets and development of potential newer therapeutic agents. Those found to retard the progression of experimental CP and fibrosis in animal models include interferon (IFN) beta and IFN-gamma; a Japanese herbal medicine called Saiko-keishi-to (TJ-10); curcumin; PPAR-gamma ligand (troglitazone); antioxidants (vitamin A, vitamin E, DA 9601 and epigallocatechin-3-gallate); a protease inhibitor (camostat mesilate) and hydroxymethylglutaryl-CoA inhibitor (lovastatin). This review summarizes the current literature addressing the role of different pharmacological agents aimed at reducing or preventing inflammation and the consequent fibrogenesis in CP.

Ascorbic acid alleviates pancreatic damage induced by dibutyltin dichloride (DBTC) in rats

PURPOSE

Because previous studies have reported depleted antioxidant capacity in patients with chronic pancreatitis (CP), prevention of free radical production has gained importance in antifibrotic treatment strategies for CP. The aim of this study was to investigate the effects of ascorbic acid on oxidative capacity and pancreatic damage in experimental CP.

MATERIALS AND METHODS

CP was induced in male Sprague-Dawley rats by infusion of dibutyltin dichloride (DBTC) into the tail vein. Ascorbic acid was given intraperitoneally at a daily dose of 10 mg/kg body weight. The treatment groups were as follows: group 1, DBTC plus intraperitoneal physiologic saline; group 2, DBTC plus intraperitoneal ascorbic acid; group 3, solvent plus intraperitoneal physiologic saline; group 4, no operation plus intraperitoneal physiologic saline. Each group contained 15 animals. Treatment was started after CP was established. After 4 weeks of treatment, serum hyaluronic acid and laminin levels were determined by radioimmunoassay, pancreatic tissue oxidative stress was analyzed, and the degree of pancreatic damage was determined.

RESULTS

Ascorbic acid treatment markedly increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) concentrations in pancreatic tissue (p < 0.01 for both). Significant serum hyaluronic acid and laminin reductions were observed in group 2 as compared with group 1 (p < 0.05). However, the serum hyaluronic acid and laminin levels remained elevated when compared with those of groups 3 and 4 (p < 0.05). Histopathologic scores were also lower in animals with CP that underwent ascorbic acid-treatment (p < 0.05).

CONCLUSION

Ascorbic acid treatment alleviated the degree of oxidative stress and pancreatic damage in rat CP. Antioxidant treatment might be considered a potential option to improve the pathologic process in CP.

Allopurinol in rat chronic pancreatitis: effects on pancreatic stellate cell activation

OBJECTIVES

Activation of pancreatic stellate cells (PSCs) is a key event in pancreatic fibrosis. Xanthine oxidase-derived free radicals are involved in the mechanism of chronic pancreatitis (CP). We here searched the in vivo effects of allopurinol on PSC activation and its relation to tissue oxidative stress and histological findings in rat CP.

METHODS

Rat CP was induced with intraductal trinitrobenzene sulfonic acid in groups 1 (n = 16) and 2 (n = 10). Group 3 (n = 10) received intraductal saline. Four weeks after induction, group 1 received allopurinol (200 mg/kg, s.c.), and groups 2 and 3 received saline. After 4 weeks, oxidative stress parameters, histological evaluation, and immunostaining for alpha-smooth muscle actin (+) PSCs were performed in the pancreata.

RESULTS

Oxidative stress parameters improved significantly in group 1 compared with groups 2 and 3. Collagen deposition and lobular/sublobular atrophy were significantly lower in group 1 than in group 2. Alpha-smooth muscle actin (+) PSCs counts in group 1 were significantly lower than in group 2, and were in correlation with the degree of fibrosis and atrophy.

CONCLUSIONS

Allopurinol inhibits PSC activation in vivo. Pancreatic fibrosis can be prevented, at least in part, by antioxidant treatment through xanthine oxidase metabolism. Long-term use of allopurinol and its analogs may be considered in clinical trials with CP.

Ethanol augments PDGF-induced NADPH oxidase activity and proliferation in rat pancreatic stellate cells

BACKGROUND/AIMS

Activated stellate cells are considered the principal mediators of chronic alcoholic pancreatitis/fibrosis. However the mechanisms of alcohol action on pancreatic stellate cells (PaSCs) are poorly understood. The aims of this study were to determine the presence and role of the NADPH oxidase system in mediating alcohol effects on PaSCs with specific emphasis on proliferation.

METHODS

PaSC NADPH oxidase components mRNA and protein were determined by RT-PCR and Western blot. The NADPH oxidase activity was measured by detecting the production of reactive oxygen species using lucigenin-derived chemiluminescence assay. PaSC DNA synthesis, a measure of proliferation, was performed by determining the [3H] thymidine incorporation into DNA.

RESULTS

mRNA for NADPH oxidase components Nox1, gp91(phox), Nox4, p22(phox), p47(phox) and p67(phox) and protein for NADPH oxidase subunits gp91(phox), p22(phox), p47(phox) and p67(phox) are present in PaSCs. Treatment with platelet-derived growth factor (PDGF) significantly increased the NADPH oxidase activity and DNA synthesis in cultured PaSCs. Alcohol treatment markedly augmented both the NADPH oxidase activity and the DNA synthesis caused by PDGF, which was prevented by antioxidant N-acetyl-L-cysteine, ROS scavenger tiron, and the NADPH oxidase inhibitor diphenylene iodium. The effects of PDGF on NADPH oxidase activity and DNA synthesis were prevented in PaSCs isolated from the pancreas of mice with a genetic deficiency of p47(phox).

CONCLUSIONS

Ethanol causes proliferation of stellate cells by augmenting the activation of the cell's NADPH oxidase system stimulated by PDGF. These results provide new insights into the mechanisms of alcohol-induced fibrosing disorders.

Relationship between acute pancreatitis and oxidative stress

Under the imbalance between generation of reactive oxygen species and inadequate antioxidant defense systems, oxidative stress can cause cell damage either directly or indirectly through altering signaling pathways. It is the etiopathogenisis and also the consequence of many diseases. Oxidative injury plays an important role not only in the pathogenesis of acute pancreatitis (AP) but also in pancreatitis-induced damages of other organs such as heart, liver, lung, kidney, alimentary canal and so on. Oxidative stress can produce a higher level of reactive oxygen species (ROS) and reactive nitrogen species (RNS), which induce inflammatory reaction and microcirculation disturbance, and cell necrosis or apoptosis, leading to pancreatic inflammation and multiple organ dysfunction syndromes. The antioxidants can decrease the production of oxygen free radicals (or directly scavenge them), protect the antioxidant enzyme activity, reinforce the antioxidative capacity of bodies, and consequently play an obvious therapeutic effect on AP.

The pancreatic stellate cell: a star on the rise in pancreatic diseases

Pancreatic stellate cells (PaSCs) are myofibroblast-like cells found in the areas of the pancreas that have exocrine function. PaSCs are regulated by autocrine and paracrine stimuli and share many features with their hepatic counterparts, studies of which have helped further our understanding of PaSC biology. Activation of PaSCs induces them to proliferate, to migrate to sites of tissue damage, to contract and possibly phagocytose, and to synthesize ECM components to promote tissue repair. Sustained activation of PaSCs has an increasingly appreciated role in the fibrosis that is associated with chronic pancreatitis and with pancreatic cancer. Therefore, understanding the biology of PaSCs offers potential therapeutic targets for the treatment and prevention of these diseases.