Kinetic study of TNF-alpha production and its regulatory mechanisms in acinar cells during acute pancreatitis induced by bile-pancreatic duct obstruction

Redox signaling in the pancreas in health and disease

This review addresses oxidative stress and redox signaling in the pancreas under healthy physiological conditions as well as in acute pancreatitis, chronic pancreatitis, pancreatic cancer, and diabetes. Physiological redox homeodynamics is maintained mainly by NRF2/KEAP1, NF-κB, protein tyrosine phosphatases, peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α), and normal autophagy. Depletion of reduced glutathione (GSH) in the pancreas is a hallmark of acute pancreatitis and is initially accompanied by disulfide stress, which is characterized by protein cysteinylation without increased glutathione oxidation. A cross talk between oxidative stress, MAPKs, and NF-κB amplifies the inflammatory cascade, with PP2A and PGC1α as key redox regulatory nodes. In acute pancreatitis, nitration of cystathionine-β synthase causes blockade of the transsulfuration pathway leading to increased homocysteine levels, whereas p53 triggers necroptosis in the pancreas through downregulation of sulfiredoxin, PGC1α, and peroxiredoxin 3. Chronic pancreatitis exhibits oxidative distress mediated by NADPH oxidase 1 and/or CYP2E1, which promotes cell death, fibrosis, and inflammation. Oxidative stress cooperates with mutant KRAS to initiate and promote pancreatic adenocarcinoma. Mutant KRAS increases mitochondrial reactive oxygen species (ROS), which trigger acinar-to-ductal metaplasia and progression to pancreatic intraepithelial neoplasia (PanIN). ROS are maintained at a sufficient level to promote cell proliferation, while avoiding cell death or senescence through formation of NADPH and GSH and activation of NRF2, HIF-1/2α, and CREB. Redox signaling also plays a fundamental role in differentiation, proliferation, and insulin secretion of β-cells. However, ROS overproduction promotes β-cell dysfunction and apoptosis in type 1 and type 2 diabetes.

Redesigning Berberines and Sanguinarines to Target Soluble Epoxide Hydrolase for Enhanced Anti-Inflammatory Efficacy

Amino-berberine has remained underexplored due to limited biological evaluation and total synthesis approaches. In inflammation therapy, soluble Epoxide Hydrolase (sEH) is a promising target, yet natural scaffolds remain underutilized. Our study advances the field by redesigning natural compounds─berberine and sanguinarine─with strategic urea modifications and hydrogenated frameworks, creating novel sEH inhibitors with enhanced in vivo efficacy. Through total synthesis and structure-activity relationship studies of amino-berberine derivatives, chiral tetrahydroberberine (R)-14i (coded LXZ-42) emerged as the most potent lead, with an IC50 value of 1.20 nM. (R)-14i showed reduced CYP enzyme impact, potent therapeutic effects on acute pancreatitis, no acute in vivo toxicity, and superior pharmacokinetic properties, with an oral bioavailability of 89.3%. Structural insights from crystallography of (R)-14i bound to sEH revealed key interactions: three with the tetrahydroberberine framework and three hydrogen bonds with the urea group, highlighting (R)-14i as a novel lead for sEH-targeted therapies in inflammation.

Discovery of Orally Active Phenylquinoline-Based Soluble Epoxide Hydrolase Inhibitors with Anti-Inflammatory and Analgesic Activity

Currently, there are no specific drugs for treating acute pancreatitis. Soluble epoxide hydrolase (sEH) inhibitors show promise, but face challenges like low blood drug concentrations and potential adverse effects on CYP enzymes and the human ether-a-go-go-related gene (hERG). In this study, an approach involving scaffold hopping and structure-activity guided optimization was employed to design a series of phenylquinoline-based sEH inhibitors. Among these compounds, DJ-53 exhibited potent in vitro and in vivo effects in alleviating pain and reducing inflammation. The in vivo mechanism of action involved inhibiting sEH enzyme activity, thereby increasing levels of anti-inflammatory epoxyeicosatrienoic acids (EETs) and decreasing levels of proinflammatory dihydroxyeicosatrienoic acids (DHETs). Importantly, DJ-53 showed exceptional oral bioavailability and pharmacokinetics, while avoiding inhibition of CYP enzymes or the hERG channel. These results highlight DJ-53's potential as a new lead compound for anti-inflammatory and analgesic applications and provide a safe and effective scaffold for developing sEH inhibitors.

Severity of acute pancreatitis in patients with inflammatory bowel disease in the era of biologics: A propensity-score-matched analysis using a nationwide database in Japan

Background and Aim

Acute pancreatitis (AP) is a rare extraintestinal manifestation of inflammatory bowel disease (IBD). Several studies from Western countries have reported that the severity of AP in patients with IBD is similar to that in the general population; however, its severity in patients from Eastern countries in the era of biologics remains unclear. This study aimed to investigate the severity of AP in patients with IBD and the effect of biologics on the severity of AP using a nationwide database.

Methods

We divided 1138 eligible AP admissions from the Diagnosis Procedure Combination database system into IBD and non-IBD groups after propensity score matching, and compared the severity of AP. We divided the IBD group into ulcerative colitis (UC) and Crohn's disease (CD) subgroups and compared each with the non-IBD group. Logistic regression analysis was conducted to identify the clinical factors affecting acute pancreatitis.

Results

IBD and UC groups had lower rate of severe AP compared to the non-IBD group (13.7% vs 28.3%, P < 0.0001 and 11.0% vs 28.3%, P < 0.0001, respectively). There were no differences in the rates of severe AP between the CD and non-IBD groups. Multivariate analysis showed that biologics did not affect the severity of AP.

Conclusion

The severity of AP in patients with IBD may be lower than that in the general population; biologics for IBD may not worsen its severity. Further prospective studies are required to clarify the severity of AP in patients with IBD.

The Role of Mesenchymal Stem Cells with Ascorbic Acid and N-Acetylcysteine on TNF-α, IL 1β, and NF-κβ Expressions in Acute Pancreatitis in Albino Rats

Severe acute pancreatitis (SAP) is a necrotic pancreatic inflammation associated with high mortality rate (up to 70%). Bone marrow (BM) mesenchymal stem cells (MSCs) have been investigated in pancreatic cellular regeneration, but still their effects are controversial. Therefore, the present study is aimed at examining the enrichment of the stem cells with ascorbic acid (AA) and N-acetylcysteine (NAC) and explore their combined action on the expression of the inflammatory cytokines: interleukin 1β (IL 1β), tumor necrosis factor-α (TNF-α), and nuclear factor-κβ (NF-κβ). A total of twenty adult male Sprague-Dawley albino rats were divided into four groups: the control group, cerulein group (to induce acute pancreatitis), BM-MSCs group, and combined BM-MSCs with AA and NAC group. Homing and proliferation of stem cells were revealed by the appearance of PKH26-labelled BM-MSCs in the islets of Langerhans. AA and NAC combination with BM-MSCs (group IV) was demonstrated to affect the expression of the inflammatory cytokines: IL 1β, TNF-α, and NF-κβ. In addition, improvement of the biochemical and histological parameters is represented in increasing body weight, normal blood glucose, and insulin levels and regeneration of the islet cells. Immunohistochemical studies showed an increase in proliferating cell nuclear antigen (PCNA) and decrease in caspase-3 reactions, detected markedly in group IV, after the marked distortion of the classic pancreatic lobular architecture was induced by cerulein. It could be concluded that treatment with BM-MSCs combined with antioxidants could provide a promising therapy for acute pancreatitis and improve the degeneration, apoptosis, necrosis, and inflammatory processes of the islets of Langerhans. TNF-α, IL 1β, and NF-κβ are essential biomarkers for the evaluation of MSC regenerative effectiveness.

Emerging Therapies to Prevent Post-ERCP Pancreatitis

PURPOSE OF REVIEW

The aim of this review is to evaluate emerging, novel therapies for the prevention of post-ERCP pancreatitis.

RECENT FINDINGS

Rectal indomethacin reduces the risk of pancreatitis in low- and average-risk patients, who comprise the majority of patients undergoing ERCP. An 8-h protocol of aggressive lactated Ringer's reduces the risk of pancreatitis in average-risk patients. Sublingual nitrate may provide additional benefit to rectal NSAIDs in preventing PEP. A tacrolimus trough > 2.5 ng/mL was recently shown to be associated with a lower risk of PEP in liver transplant patients undergoing ERCP. Routine usage of rectal indomethacin in all patients undergoing ERCP reduces the risk of PEP. Pancreatic-duct stents reduce the risk of PEP in high-risk patients. There is emerging data that aggressive hydration with lactated Ringer's and nitrates may further reduce PEP. Tacrolimus is a promising potential agent to prevent PEP but needs further clinical study.

Protease inhibitors, inflammatory markers, and their association with outcome in dogs with naturally occurring acute pancreatitis

Background

Acute pancreatitis (AP) presumably is associated with pancreatic protease activation, protease inhibitor (PI) depletion, and inflammatory mediator secretion.

Objectives

Examine PIs and inflammatory mediator concentrations in dogs with AP and their association with death.

Animals

Thirty‐one dogs diagnosed with AP based on clinical signs, ultrasonographic findings, and increased canine pancreatic lipase immunoreactivity (cPLI) and 51 healthy control dogs.

Methods

Antithrombin and α₂‐antiplasmin activity (ATA and α₂AP, respectively) and concentrations of α₁‐proteinase inhibitor (α₁PI), α₂‐macroglobulin (α₂MG), C‐reactive protein (CRP), interleukins (ILs)‐2,6,8 and tumor necrosis factor‐α (TNF‐α) were prospectively measured. Severity of AP was assessed by clinical severity scoring systems.

Results

Mortality rate was 19%. Antithrombin activity was lower (P = .004) and maximal CRP, IL‐6, and TNF‐α concentrations higher (P < .04) in the AP group compared to the controls, whereas IL‐2, IL‐8, α₁PI, and α₂AP concentrations did not differ between groups. Serum α₂MG concentration was not reliably detected. Serum cPLI, CRP, and IL‐6 concentrations were significantly and positively correlated. The ATA was lower (P = .04), and canine acute pancreatitis severity (CAPS) scores higher (P = .009) in nonsurvivors compared to survivors. Higher CAPS scores were associated (P < .05) with decreased ATA and increased cPLI, CRP, and IL‐6 concentrations.

Conclusions and Clinical Importance

Systemic inflammation in dogs with AP is manifested by increased inflammatory mediator concentrations, correlating with cPLI and CRP concentrations. Hypoantithrombinemia is associated with death. Serum concentrations of α₂AP and α₁PI are less useful prognostic markers. The CAPS score is a useful prognostic marker in dogs with AP.

Heparanase in Acute Pancreatitis

Acute pancreatitis (AP) is one of the most common diseases in gastroenterology, affecting 2% of all hospitalized patients. Nevertheless, neither the etiology nor the pathophysiology of the disease is fully characterized, and no specific or effective treatment has been developed. Heparanase (Hpa) is an endoglycosidase that cleaves heparan sulfate (HS) side chains of heparan sulfate proteoglycans (HSPGs) into shorter oligosaccharides, activity that is highly implicated in cell invasion associated with cancer metastasis and inflammation. Given that AP is a typical inflammatory disease, we investigated whether Hpa plays a role in AP. Our results provide keen evidence that Hpa expression and activity are significantly increased following cerulein-induced AP in wild type mice. In parallel to the classic manifestations of AP, namely elevation of amylase and lipase levels, pancreas edema and inflammation as well as induction of cytokines and signaling molecules, have been detected in this experimental model of the disease. Noteworthy, these features were far more profound in transgenic mice overexpressing heparanase (Hpa-Tg), suggesting that these mice can be utilized as a model system to reveal the molecular mechanism by which Hpa functions in AP. Further support for the involvement of Hpa in the pathogenesis of AP emerged from our observation that treatment of experimental AP with PG545 or SST0001(= Ronepastat), two potent Hpa inhibitors, markedly attenuated the biochemical, histological and immunological manifestations of the disease. Hpa, therefore, emerges as a potential new target in AP, and Hpa inhibitors are hoped to prove beneficial in AP along with their promising efficacy as anti-cancer compounds.

Visnagin attenuates acute pancreatitis via Nrf2/NFκB pathway and abrogates associated multiple organ dysfunction

Acute pancreatitis (AP) is an exocrine dysfunction of the pancreas where oxidative stress and inflammatory cytokines play a key role in induction and progression of the disease. Studies have demonstrated that antioxidant phytochemicals have been effective in improving pancreatitis condition, but there are no clinically approved drugs till date. Our study aims to assess the preventive activity of visnagin, a novel phytochemical isolated from Ammi visnaga against cerulein induced AP. Male Swiss albino mice were divided into six groups (n = 6, each group) comprising of normal control, cerulein control, seven day pre-treatment with visnagin at three dose levels; visnagin low dose (10 mg/kg), visnagin mid dose (30 mg/kg), visnagin high dose (60 mg/kg) and visnagin control (60 mg/kg). AP was induced by six injections of cerulein (50 μg/kg, i.p.) on the 7^th day and the animals were sacrificed after 6 h of last cerulein dose. Various markers of pancreatic function, oxidative stress and inflammation were assessed. Visnagin was found to be effective in reducing plasma amylase and lipase levels, reduced cerulein induced oxidative stress. Visnagin dose dependently decreased the expression of IL-1β, IL-6, TNF-α and IL-17. It attenuated the levels of nuclear p65-NFκB. Visnagin improved the antioxidant defence by improving Nrf2 expression and halted pancreatic inflammation by suppressing NFκB and nitrotyrosine expression in the acinar cells. Further, it attenuated the expression of markers of multiple organ dysfunction syndrome and reduced inflammatory cytokines in lungs and intestine. Cumulatively, these findings indicate that visnagin has substantial potential to prevent cerulein induced AP.

Inflammatory stimuli promote oxidative stress in pancreatic acinar cells via Toll-like receptor 4/nuclear factor-κB pathway

The Toll‑like receptor 4/nuclear factor‑κB (TLR4/NF‑κB) pathway is vital to the pathogenesis of acute pancreatitis (AP). The aim of the present study was to identify the mechanism of the activation of the TLR4/NF‑κB signaling pathway in the viability of primary pancreatic cells. The cells were stimulated with lipopolysaccharide (LPS) for the activation of NF‑κB signaling. Next, the reactive oxygen species (ROS) level was evaluated by detecting the concentration of malondialdehyde and glutathione peroxidase. Cell viability was measured by Cell Counting Kit‑8 and MTT assays, while the percentage of apoptosis was detected by flow cytometry. Quantitative polymerase chain reaction was used to detect TLR4, B‑cell lymphoma 2 (Bcl2), Bcl2‑associated X protein (Bax) and phorbol‑12‑myristate‑13‑acetate‑induced protein 1 (PMAIP1) expression levels. Western blot assay was also conducted to detect TLR4 protein expression, while the activity of NF‑κB signaling was measured by determining the p65 and phosphorylated p65 protein levels. In addition, the effect of TLR4 overexpression or treatment with TLR4 antagonists in the presence of LPS stimulation was investigated. The results revealed that ROS levels were increased and cell viability was decreased in LPS‑stimulated pancreatic acinar cells. TLR4, Bax and PMAIP1 levels were increased, Bcl2 expression was decreased and NF‑κB signaling was activated in LPS‑stimulated pancreatic acinar cells. Furthermore, pancreatic cells with TLR4 overexpression exhibited increased ROS level and decreased viability. Finally, the effect caused by LPS stimulation was partially reversed by treatment of pancreatic acinar cells with TLR4 antagonists. In conclusion, the current study investigated a novel regulatory mechanism of the TLR4/NF‑κB pathway in LPS‑stimulated pancreatic cells, which may contribute to pancreatitis. The damage of these cells due to increased ROS levels was observed to occur through activation of the TLR4/NF‑κB pathway.

Immunomodulatory mechanisms of mesenchymal stem cells and their therapeutic applications

In the recent years, many studies have shown that MSCs must be stimulated by pro-inflammatory cytokines or other immune mediators before they can modulate immune cells in inflamed and damaged tissues. MSCs appear to be involved in inducing several regulatory immune cells, such as Tregs, Bregs, and regulatory NK cells. This new immune milieu created by MSCs may establish a tolerogenic environment that leads to an optimal condition for the treatment of immune diseases. The mechanisms of MSC action to treat immune disorders need to be further investigated in more detail. Since there have been some contradictory outcomes of clinical trials, it is necessary to perform large-scale and randomized clinical studies, such as a phase 3 placebo-controlled double-blind study of a third party MSCs to optimize MSC administration and to prove safety and efficacy of MSC treatment. MSCs offer great therapeutic promise, especially for the treatment of difficult-to-treat immune diseases.

Picroside II Shows Protective Functions for Severe Acute Pancreatitis in Rats by Preventing NF-κB-Dependent Autophagy

Picroside II, from the herb Picrorhiza scrophulariiflora Pennell, has antioxidant and anti-inflammatory activities. However, its function on severe acute pancreatitis (SAP) and molecular mechanism remains unknown. The effects of picroside II on the SAP induced by cerulean were investigated. SAP rats were treated with picroside II (25 mg/kg). The severity of SAP was evaluated by using biochemical and histological analyses. Pancreatic cancer cell PANC-1 was transfected with ptfLC3 (an indicator of autophagic activity), pcDNA3.1-NF-κB (nuclear factor kappa B), and pTZU6+1-NF-κB-shRNA and then treated with picroside II. Relative molecules related with NF-κB-dependent autophagy were detected by using Western blot. Autophagic activities were observed by phase-contrast and fluorescent microscopes. Acetylated LC3 was detected by immunoprecipitation. The results showed that picroside II treatment reduced the level of ALT, AST, NF-κB, IL-1β, IL-6, TNF-α, and SIRT1 (NAD⁺-dependent deacetylase) and increased the level of SOD and GSH. The autophagic activity was reduced when NF-κB was silenced, and the levels of TNF-α and SIRT1 were reduced. In contrast, the overexpression of NF-κB increased autophagic activity and the level of TNF-α, which activated SIRT1. SIRT1 deacetylated LC3 and increased autophagic activities. Picroside II ameliorates SAP by improving antioxidant and anti-inflammtory activities of SAP models via NF-κB-dependent autophagy.

Oxidized phospholipids exert a dual effect on bile acid-induced CCL2 expression in pancreatic acini

BACKGROUND

oxidized phospholipids (oxPLs) generated in inflammatory diseases could play a key role by inducing pro- and anti-inflammatory effects. OBJETIVES: we investigated the effect of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and oxidized POPC (oxPOPC) in the inflammatory response triggered in pancreatic acini.

METHODS

control acini were incubated in the absence or presence of either POPC or oxPOPC (≤100 μM). In additional experiments, oxPOPC effects were evaluated in sodium taurocholate (NaTc)-treated acini. CCL2 and TLR4 mRNA expression was analyzed by RT-qPCR. By western blot, JNK-MAPK, JAK and IκBα in cytoplasm as well as p65-NF-kB and p-STAT3 in the nucleus were evaluated. The involvement of TLR4, JNK-MAPK, JAK as well as NF-kB, STAT3 and PPARγ was assessed using pharmacological inhibition.

RESULTS

no effect was found in response to POPC. Conversely, in response to oxPOPC (10 μM), JNK-MAPK and JAK acted as TLR4-downstream signals, leading to CCL2 upregulation mainly through NF-kB activation. Moreover, TLR4 non-dependent mechanisms induced STAT3 activation in oxPOPC-treated acini. Mediated by PPARγ, oxPOPC (50 μM) inhibited the CCL2 overexpression found in NaTc-treated acini.

CONCLUSIONS

oxPOPC exerts pro- and anti-inflammatory effects in pancreatic acinar cells mediated by TLR4 and PPARγ signals, respectively. This dual action proved to be dependent on the concentration. The molecular mechanisms involved in the oxPL response could be useful for new therapeutic approaches to the treatment of oxPLs-related inflammatory pathologies.

Antioxidant Effect of Ukrain Versus N-Acetylcysteine Against Acute Biliary Pancreatitis in An Experimental Rat Model

Purpose/Aim: Oxidative stress plays an important role in the pathogenesis of acute pancreatitis (AP). We compared the therapeutic effects of Ukrain (NSC 631570) and N-acetylcysteine (NAC) in rats with AP.

MATERIALS AND METHODS

Forty male Sprague Dawley rats were divided into four groups: controls; AP; AP with NAC; and AP with Ukrain. AP was induced via the ligation of the bile-pancreatic duct; drugs were administered intraperitoneally (i.p.) 30 min and 12 h after AP induction. Twenty-four hours after AP induction, animals were sacrificed and the pancreas was excised. Levels of malondialdehyde (MDA) and nitric oxide (NO), and activity levels of tumor necrosis factor (TNF)-α, and myeloperoxidase (MPO) were measured in tissue samples. Total oxidant status (TOS), total antioxidant status (TAS), and total bilirubin, as well as activity levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), amylase and lipase were measured in serum samples. Pancreatic tissue histopathology was also evaluated.

RESULTS

Test drugs reduced levels of MDA, NO, TNF-α, total bilirubin, AST, ALT, TOS and MPO, amylase and lipase activities (P < 0.001), and increased TAS (P < 0.001). Rats treated with test drugs attenuated AP-induced morphologic changes and decreased pancreatic damage scores compared with the AP group (P < 0.05). Both test drugs attenuated pancreatic damage, but the therapeutic effect was more pronounced in rats that received Ukrain than in those receiving NAC.

CONCLUSIONS

These results suggest that treatment with Ukrain or NAC can reduce pancreatic damage via anti-inflammatory and antioxidant effects.

Baicalein protect pancreatic injury in rats with severe acute pancreatitis by inhibiting pro-inflammatory cytokines expression

BACKGROUND/AIM

Inflammatory cytokines is a key point in the development of pathogenesis of SAP. Inflammatory mediators TNF-α and IL-6 are up-regulated in serum of patients with SAP and become good discriminators of SAP severity.

MATERIALS AND METHODS

In this study, we investigated the treatment effectiveness of Baicalein on SAP rat model. Baicalein was intravenously injected immediately after SAP induction in rats. The mortality, histopathology score, ascites fluid volume, and pro-inflammatory cytokine production were evaluated at 12 h after SAP induction.

RESULTS

Baicalein decreased the pancreatic histopathology score, reduced ascites fluid production, protected against pancreatic injury, and improved survival in rats with SAP. The serum IL-6 and TNF-α concentrations were also down-regulated by Baicalein.

CONCLUSION

Baicalein demonstrated a well curative capability on rats with SAP. The mechanism may be alleviateing pancreatic injury and inhibiting pro-inflammatory cytokines expression.

Redox signaling in acute pancreatitis

Acute pancreatitis is an inflammatory process of the pancreatic gland that eventually may lead to a severe systemic inflammatory response. A key event in pancreatic damage is the intracellular activation of NF-κB and zymogens, involving also calcium, cathepsins, pH disorders, autophagy, and cell death, particularly necrosis. This review focuses on the new role of redox signaling in acute pancreatitis. Oxidative stress and redox status are involved in the onset of acute pancreatitis and also in the development of the systemic inflammatory response, being glutathione depletion, xanthine oxidase activation, and thiol oxidation in proteins critical features of the disease in the pancreas. On the other hand, the release of extracellular hemoglobin into the circulation from the ascitic fluid in severe necrotizing pancreatitis enhances lipid peroxidation in plasma and the inflammatory infiltrate into the lung and up-regulates the HIF-VEGF pathway, contributing to the systemic inflammatory response. Therefore, redox signaling and oxidative stress contribute to the local and systemic inflammatory response during acute pancreatitis.

Chronic alcohol exposure exacerbates inflammation and triggers pancreatic acinar-to-ductal metaplasia through PI3K/Akt/IKK

Pancreatic acinar-to-ductal metaplasia (ADM) has been identified as an initiating event that can progress to pancreatic intraepithelial neoplasia (PanIN) or pancreatic ductal adenocarcinoma (PDAC). Acini transdifferentiation can be induced by persistent inflammation. Notably, compelling evidence has emerged that chronic alcohol exposure may trigger an inflammatory response of macrophages/monocytes stimulated by endotoxins. In the present study, we aimed to evaluate the role of inflammation induced by chronic alcohol and lipopolysaccharide (LPS) exposure in the progression of pancreatic ADM, as well as to elucidate the possible mechanisms involved. For this purpose, cultured macrophages were exposed to varying doses of alcohol for 1 week prior to stimulation with LPS. Tumor necrosis factor-α (TNF-α) and regulated upon activation, normal T cell expression and secreted (RANTES) expression were upregulated in the intoxicated macrophages with activated nuclear factor-κB (NF-κB). Following treatment with the supernatant of intoxicated macrophages, ADM of primary acinar cells was induced. Furthermore, the expression of TNF-α and RANTES, as well as the phosphatidylinositol-3-kinase (PI3K)/protein kinase B(Akt)/inhibitory κB kinase (IKK) signaling pathway have been proven to be involved in the ADM of acinar cells. Moreover, Sprague-Dawley (SD) rats were employed to further explore the induction of pancreatic ADM by chronic alcohol and LPS exposure in vivo. At the end of the treatment period, a number of physiological parameters, such as body weight, liver weight and pancreatic weight were reduced in the exposed rats. Plasma alcohol concentrations and oxidative stress levels in the serum, as well as TNF-α and RANTES expression in monocytes were also induced following chronic alcohol and LPS exposure. In addition, pancreatic ADM was induced through the PI3K/Akt/IKK signaling pathway by the augmented TNF-α and RANTES expression levels in the exposed rats. Overall, we characterized the link between inflammation induced by chronic alcohol and LPS exposure and pancreatic ADM. However, the mechanisms behind the induction of pancreatic ADM warrant further investigation.

Effectiveness of interleukin-1 receptor antagonist (Anakinra) on cerulein-induced experimental acute pancreatitis in rats

AIM

Acute pancreatitis (AP) is defined as an inflammatory disease of the pancreas. The purpose of this study was to examine the effectiveness of Anakinra on cerulein-induced experimental pancreatitis rat model by using the results of biochemical and histopathological findings.

MATERIALS AND METHODS

Cerulein was administered to induce AP in rats. Group 1 was the sham group. Subcutancerulein was injected to the rats in group 2 for experimental pancreatitis group. In groups 3 and 4, 100 and 50 mg/kg intraperitoneal Anakinra were injected after the induction of experimental pancreatitis by subcutaneous cerulein in rats, respectively. Lastly, in group 5, rats were injected with intraperitoneal saline and subcutan cerulean for placebo group. The following parameters were evaluated: histopathological score of pancreatitis, apoptotic index, amylase, lipase, TNF-α levels, IL-1β and the leukocyte count.

RESULTS

When the results of serum amylase, lipase, TNF-α and IL-1β levels, the leukocyte count, histopathologic scores and apoptotic indices of control group compared to the results of other groups, the differences exhibited statistical significance (all p < 0.05). On the other hand, when the results of fourth group compared with the results of third group, the data demonstrated statistical insignificance (p > 0.05). However, no any significant differences were found between the results of fourth and fifth groups (p > 0.05).

CONCLUSION

In the light of these results, cerulein is an appropriate agent for experimental AP rat model and Anakinra has a favorable therapeutic effect on acute experimental pancreatitis model. Moreover, Anakinra significantly decreases cerulein-related pancreatic tissue injury and pancreatic apoptosis.

Anti-TNF therapy in the treatment of psoriasis in a patient with acute-on-chronic pancreatitis

BACKGROUND

Psoriasis is accepted as a multisystemic disease with several important systemic manifestations. Thus, underlying comorbidities have to be taken into account in the choice of treatment.

OBJECTIVE

To explore the role of anti-TNF therapy in the treatment of psoriasis in a patient with acute-on-chronic pancreatitis.

METHODS

Here, we present the case of a 75-year-old patient with severe psoriasis also suffering from chronic alcohol-induced pancreatitis with recurrent acute flares. A recent life-threatening episode of acute pancreatitis and ischemic liver precluded the reintroduction of methotrexate. Cyclosporine was also excluded as it has been reported to induce acute pancreatitis. Thus, an anti-TNF treatment was initiated in close collaboration with a gastroenterologist.

RESULTS

A year after starting anti-TNF therapy the patient continues to show complete clinical remission of his psoriasis. No side effects, particularly no bacterial infections, were reported. No relapses of the patient's underlying chronic pancreatitis were observed throughout the entire treatment with regular clinical and laboratory monitoring, suggesting that chronic pancreatitis is not per se a contraindication for anti-TNF therapy.

CONCLUSION

This case study opens the way for further questioning on the role of TNF in the pathogenesis of chronic and acute pancreatitis and the use of anti-TNF therapy in its treatment.

Necro-inflammatory response of pancreatic acinar cells in the pathogenesis of acute alcoholic pancreatitis

The role of pancreatic acinar cells in initiating necro-inflammatory responses during the early onset of alcoholic acute pancreatitis (AP) has not been fully evaluated. We investigated the ability of acinar cells to generate pro- and anti-inflammatory mediators, including inflammasome-associated IL-18/caspase-1, and evaluated acinar cell necrosis in an animal model of AP and human samples. Rats were fed either an ethanol-containing or control diet for 14 weeks and killed 3 or 24 h after a single lipopolysaccharide (LPS) injection. Inflammasome components and necro-inflammation were evaluated in acinar cells by immunofluorescence (IF), histology, and biochemical approaches. Alcohol exposure enhanced acinar cell-specific production of TNFα, IL-6, MCP-1 and IL-10, as early as 3 h after LPS, whereas IL-18 and caspase-1 were evident 24 h later. Alcohol enhanced LPS-induced TNFα expression, whereas blockade of LPS signaling diminished TNFα production in vitro, indicating that the response of pancreatic acinar cells to LPS is similar to that of immune cells. Similar results were observed from acinar cells in samples from patients with acute/recurrent pancreatitis. Although morphologic examination of sub-clinical AP showed no visible signs of necrosis, early loss of pancreatic HMGB1 and increased systemic levels of HMGB1 and LDH were observed, indicating that this strong systemic inflammatory response is associated with little pancreatic necrosis. These results suggest that TLR-4-positive acinar cells respond to LPS by activating the inflammasome and producing pro- and anti-inflammatory mediators during the development of mild, sub-clinical AP, and that these effects are exacerbated by alcohol injury.

Effects of hydrogen-rich saline on taurocholate-induced acute pancreatitis in rat

Oxidative stress plays an important role in the pathogenesis of acute pancreatitis (AP). As an ideal exterminator of poisonous free radicals, hydrogen can clearly reduce the degree of oxidative damage caused by severe acute pancreatitis (SAP) and lessen the presence of inflammatory cytokines. The aim of this study was to investigate the effects and mechanism of hydrogen-rich saline on SAP in rats. Serum TNF- α , IL-6, and IL-18 and histopathological score in the pancreas were reduced after hydrogen-rich saline treatment. Malondialdehyde (MDA) and myeloperoxidase (MPO) contents were obviously reduced, while superoxide dismutase (SOD) and glutathione (GSH) contents were increased after hydrogen-rich saline treatment. The expression of mRNA of tumor necrosis factor- α (TNF- α ) and intercellular adhesion molecule-1 (ICAM-1) in the pancreas was reduced in hydrogen-rich saline treated group. In conclusion, intravenous hydrogen-rich saline injections could attenuate the severity of AP, probably via inhibiting the oxidative stress and reducing the presence of inflammatory mediators.

N-acetylcysteine improves pancreatic microcirculation and alleviates the severity of acute necrotizing pancreatitis

BACKGROUND/AIMS

To investigate the beneficial effect of N-Acetylcysteine (NAC) on pancreatic microvascular perfusion in acute necrotizing pancreatitis (ANP).

METHODS

Fifty-four rats were divided into a control group, an ANP group and an NAC-treated group. The ANP model was established by a retrograde injection of 3% sodium taurocholate into the pancreatic duct. The NAC-treated group received an intravenous infusion of NAC just 2 hours before and 30 minutes after the induction of ANP. The pancreatic microvascular perfusion was measured with laser Doppler flowmetry and pancreatic samples were collected for histological examination.

RESULTS

The microvascular perfusion in the NAC-treated group decreased slightly and exhibited a significant increase compared to the ANP group (p<0.01). A pathological examination revealed that edema and inflammatory infiltration decreased, and the hemorrhaging and necrosis of the pancreas were significantly reduced.

CONCLUSIONS

NAC could improve pancreatic microvascular perfusion and alleviate the severity of sodium taurocholate-induced ANP, possibly representing a new therapeutic approach to prevent the progression of ANP.

Redox signaling and histone acetylation in acute pancreatitis

Histone acetylation via CBP/p300 coordinates the expression of proinflammatory cytokines in the activation phase of inflammation, particularly through mitogen-activated protein kinases (MAPKs), nuclear factor-κB (NF-κB), and signal transducers and activators of transcription (STAT) pathways. In contrast, histone deacetylases (HDACs) and protein phosphatases are mainly involved in the attenuation phase of inflammation. The role of reactive oxygen species (ROS) in the inflammatory cascade is much more important than expected. Mitochondrial ROS act as signal-transducing molecules that trigger proinflammatory cytokine production via inflammasome-independent and inflammasome-dependent pathways. The major source of ROS in acute inflammation seems to be NADPH oxidases, whereas NF-κB, protein phosphatases, and HDACs are the major targets of ROS and redox signaling in this process. There is a cross-talk between oxidative stress and proinflammatory cytokines through serine/threonine protein phosphatases, tyrosine protein phosphatases, and MAPKs that greatly contributes to amplification of the uncontrolled inflammatory cascade and tissue injury in acute pancreatitis. Chromatin remodeling during induction of proinflammatory genes would depend primarily on phosphorylation of transcription factors and their binding to gene promoters together with recruitment of histone acetyltransferases. PP2A should be considered a key modulator of the inflammatory cascade in acute pancreatitis through the ERK/NF-κB pathway and histone acetylation.

Oxidative and nitrosative stress in acute pancreatitis. Modulation by pentoxifylline and oxypurinol

Reactive oxygen species are considered mediators of the inflammatory response and tissue damage in acute pancreatitis. We previously found that the combined treatment with oxypurinol - as inhibitor of xanthine oxidase- and pentoxifylline - as inhibitor of TNF-α production-restrained local and systemic inflammatory response and decreased mortality in experimental acute pancreatitis. Our aims were (1) to determine the time-course of glutathione depletion and oxidation in necrotizing pancreatitis in rats and its modulation by oxypurinol and pentoxifylline; (2) to determine whether TNF-α is responsible for glutathione depletion in acute pancreatitis; and (3) to elucidate the role of oxidative stress in the inflammatory cascade in pancreatic AR42J acinar cells. We report here that oxidative stress and nitrosative stress occur in pancreas and lung in acute pancreatitis and the co-treatment with oxypurinol and pentoxifylline prevents oxidative stress in both tissues. Oxypurinol was effective in preventing glutathione oxidation, whereas pentoxifylline abrogated glutathione depletion. This latter effect was independent of TNF-α since glutathione depletion occurred in mice deficient in TNF-α or its receptors after induction of pancreatitis. The beneficial effects of oxypurinol in the inflammatory response may also be ascribed to a partial inhibition of MEK1/2 activity. Pentoxifylline markedly reduced the expression of Icam1 and iNos induced by TNF-α in vitro in AR42J cells. Oxidative stress significantly contributes to the TNF-α-induced up-regulation of Icam and iNos in AR42J cells. These results provide new insights into the mechanism of action of oxypurinol and pentoxifylline as anti-inflammatory agents in acute pancreatitis.

Recent progress in understanding the pathogenesis of severe acute pancreatitis

Severe acute pancreatitis (SAP) is an acute abdominal disease that is characterized by sudden onset, quick progression, many complications and high mortality. Multiple organ dysfunction syndrome (MODS) is still regarded as the main cause of death in SAP patients. Nowadays, the mortality rate for patients with SAP in developed countries is 22.7%. In the early 21st century, the mortality reached 15.60%-23.77% in mainland China. However, the etiology, pathogenesis and pathophysiology of SAP remains unclear, resulting in puzzle or perplexity in choosing and developing treatment strategies for SAP. This paper reviews recent progress in understanding the pathogenesis of SAP.

Effects of dexamethasone on intercellular adhesion molecule 1 expression and inflammatory response in necrotizing acute pancreatitis in rats

OBJECTIVES

Adhesion molecules are involved in the inflammatory response during acute pancreatitis (AP). We investigated the effect of dexamethasone (Dx) on intercellular adhesion molecule 1 (ICAM-1) expression during AP and its consequences on leukocyte recruitment and pancreatic damage.

METHODS

Acute pancreatitis was induced in rats by 3.5% sodium taurocholate for 3 hours and 6 hours. Dexamethasone (1 mg/kg) was administered either 30 minutes before or 1 hour after inducing AP. Messenger RNA ICAM-1 expression in pancreas and lung, membrane-bound ICAM-1 in acinar cells, and ICAM-1 plasma levels were analyzed. Histological examination of the pancreas and neutrophil infiltration in pancreas and lung were also measured.

RESULTS

Prophylactic and therapeutic administration of Dx down-regulated ICAM-1 expression in pancreas and lung from early AP. Dexamethasone given before AP reduced the pancreatic damage, but lung inflammation was not prevented. Therapeutic Dx treatment was ineffective in avoiding leukocyte recruitment into the pancreas and lung in rats with AP. High ICAM-1 concentration was found in plasma during AP, which was not reduced by Dx treatments.

CONCLUSIONS

Dexamethasone down-regulates ICAM-1 expression, but it does not completely prevent leukocyte recruitment during sodium taurocholate-induced AP.

Inflammatory cytokines and intestinal barrier dysfunction in patients with severe acute pancreatitis

Severe acute pancreatitis (SAP) is often associated with intestinal barrier dysfunction (IBD). IBD is a sophisticated pathophysiological process that can lead to intestinal endotoxemia and induce systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). Inflammatory cytokines play an important role in the pathogenesis of SAP with IBD. Nuclear factor- kappa B and high mobility group box l (HMGB1) are important inflammatory cytokines that mediate the systemic inflammatory response in patients with SAP and IBD.

Essential role of monocytes and macrophages in the progression of acute pancreatitis

Acute pancreatitis (AP) is an inflammatory condition of the pancreas caused by an imbalance in factors involved in maintaining cellular homeostasis. Earliest events in AP occur within acinar cells accompanied by other principal contributors to the inflammatory response i.e. the endothelial cells, immunocytes (granulocytes, monocytes/macrophages, lymphocytes) and neutrophils. Monocytes/macrophages are important inflammatory mediators, involved in the pathophysiology of AP, known to reside in the peritoneal cavity (in the vicinity of the pancreas) and in peripancreatic tissue. Recent studies suggested that impaired clearance of injured acini by macrophages is associated with an altered cytokine reaction which may constitute a basis for progression of AP. This review focuses on the role of monocytes/macrophages in progression of AP and discusses findings on the inflammatory process involved.

Leflunomide: is a new oral agent in treatment of acute pancreatitis?

OBJECTIVES

Nuclear factor-kappaB (NF-kappaB) is a potent mediator in several steps of acute pancreatitis. Leflunomide is a novel immunomodulating drug that is also a potent inhibitor of NF-kappaB activation. The aim of this study was to investigate the effects of leflunomide pretreatment in severe necrotizing pancreatitis in rats.

METHODS

Fifty rats were randomly divided into 5 groups. Severe necrotizing pancreatitis was induced by retrograde injection of 3% sodium taurocholate into the common biliopancreatic duct. Leflunomide (10 mg/kg) was given intragastrically for 2 doses before the experiment. Serum amylase activity, pancreatic histopathologic condition, malondialdehyde level, myeloperoxidase enzyme activity, nitric oxide level, and pulmonary changes were assessed.

RESULTS

Leflunomide pretreatment significantly ameliorated pancreatic hemorrhage, edema, and neutrophil infiltration and decreased histopathological score compared with the untreated severe necrotizing pancreatitis group (pathological score [mean +/- SEM]: 6.70 +/- 1.19 vs 12.36 +/- 1.08 in the leflunomide treated and untreated groups, respectively, P < 0.01). Pulmonary changes was decreased in the leflunomide treated group (3.90 +/- 0.45 vs 4.75 +/- 0.25, respectively). Change in pulmonary alveolar distention was significant. Although serum amylase levels also decreased, the difference was not significant (5922 +/- 3290 vs 15547 +/- 5090 U/mL).

CONCLUSIONS

Leflunomide is a beneficial agent in the severe form of acute pancreatitis in rats and should be considered as a potential agent for treatment of acute pancreatitis.

Inflammatory role of the acinar cells during acute pancreatitis

Pancreatic acinar cells are secretory cells whose main function is to synthesize, store and finally release digestive enzymes into the duodenum. However, in response to noxious stimuli, acinar cells behave like real inflammatory cells because of their ability to activate signalling transduction pathways involved in the expression of inflammatory mediators. Mediated by the kinase cascade, activation of Nuclear factor-κB, Activating factor-1 and Signal transducers and activators of transcription transcription factors has been demonstrated in acinar cells, resulting in overexpression of inflammatory genes. In turn, kinase activity is down-regulated by protein phosphatases and the final balance between kinase and phosphatase activity will determine the capability of the acinar cells to produce inflammatory factors. The kinase/phosphatase pair is a redox-sensitive system in which kinase activation overwhelms phosphatase activity under oxidant conditions. Thus, the oxidative stress developed within acinar cells at early stages of acute pancreatitis triggers the activation of signalling pathways involved in the up-regulation of cytokines, chemokines and adhesion molecules. In this way, acinar cells trigger the release of the first inflammatory signals which can mediate the activation and recruitment of circulating inflammatory cells into the injured pancreas. Accordingly, the role of acinar cells as promoters of the inflammatory response in acute pancreatitis may be considered. This concept leads to amplifying the focus from leukocyte to acinar cells themselves, to explain the local inflammation in early pancreatitis.

N-acetylcysteine in acute pancreatitis

Premature trypsinogen activation and production of oxygen free radicals (OFR) are early pathogenic events which occur within acinar cells and trigger acute pancreatitis (AP). OFR exert their harmful effects on various cell components causing lipid peroxidation, disturbances in calcium homeostasis and DNA damage, which lead to increased cell injury and eventually cell death. This review presents the most recent data concerning the effects of N-Acetylcysteine (NAC), in the treatment of AP. NAC is an antioxidant capable of restoring the levels of Glutathione, the most important cellular antioxidant. Studies show the beneficial effects of NAC treatment in preventing OFR production and therefore attenuating oxidative damage. Additionally, NAC treatment has been shown to prevent the increase in cytosolic Ca²⁺ concentration and reduce the accumulation of enzymes in acinar cells during AP. The prevention, by NAC, of these pathological events occurring within acinar would contribute to reducing the severity of AP. NAC is also capable of reducing the activation of transcription factors especially sensitive to the cellular redox state, such as Nuclear factor-κB, signal transducer and activator of transcription-3 and mitogen-activated protein kinase. This leads to a down-regulation of cytokines, adhesion molecules and chemokine expression in various cell types during AP. These findings point to NAC as a powerful therapeutic treatment, attenuating oxidative-stress-induced cell injury and other pathological events at early stages of AP, and potentially contributing to reducion in the severity of disease.

Pentoxifylline prevents loss of PP2A phosphatase activity and recruitment of histone acetyltransferases to proinflammatory genes in acute pancreatitis

Mitogen-activated protein kinases (MAPKs) are considered major signal transducers early during the development of acute pancreatitis. Pentoxifylline is a phosphodiesterase inhibitor with marked anti-inflammatory properties through blockade of extracellular signal regulated kinase (ERK) phosphorylation and tumor necrosis factor alpha production. Our aim was to elucidate the mechanism of action of pentoxifylline as an anti-inflammatory agent in acute pancreatitis. Necrotizing pancreatitis induced by taurocholate in rats and taurocholate-treated AR42J acinar cells were studied. Phosphorylation of ERK and ERK kinase (MEK1/2), as well as PP2A, PP2B, and PP2C serine/threonine phosphatase activities, up-regulation of proinflammatory genes (by reverse transcription-polymerase chain reaction and chromatin immunoprecipitation), and recruitment of transcription factors and histone acetyltransferases/deacetylases to promoters of proinflammatory genes (egr-1, atf-3, inos, icam, il-6, and tnf-alpha) were determined in the pancreas during pancreatitis. Pentoxifylline did not reduce MEK1/2 phosphorylation but prevented the marked loss of serine/threonine phosphatase PP2A activity induced by taurocholate in vivo without affecting PP2B and PP2C activities. The rapid loss in PP2A activity induced by taurocholate in acinar cells was due to a decrease in cAMP levels that was prevented by pentoxifylline. Pentoxifylline also reduced the induction of early (egr-1, atf-3) responsive genes and abrogated the up-regulation of late (inos, icam, il-6, tnf-alpha) responsive genes and recruitment of transcription factors (nuclear factor kappaB and C/EBPbeta) and histone acetyltransferases to their gene promoters during pancreatitis. In conclusion, the beneficial effects of pentoxifylline--and presumably of other phosphodiesterase inhibitors--in this disease seem to be mediated by abrogating the loss of cAMP levels and PP2A activity as well as chromatin-modifying complexes very early during acute pancreatitis.

Mechanisms of dexamethasone-mediated chemokine down-regulation in mild and severe acute pancreatitis

This study aimed to investigate the role of therapeutic dexamethasone (Dex) treatment on the mechanisms underlying chemokine expression during mild and severe acute pancreatitis (AP) experimentally induced in rats. Regardless of the AP severity, Dex (1 mg/kg), administered 1 h after AP, reduced the acinar cell activation of extracellular signal-regulated kinase (ERK) and c-Jun-NH(2)-terminal kinase (JNK) but failed to reduce p38-mitogen-activated protein kinase (MAPK) in severe AP. In both AP models, Dex inhibited the activation of nuclear factor-kappaB (NF-kappaB) and signal transducers and activators of transcription (STAT) factors. All of this resulted in pancreatic down-regulation of the chemokines monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant (CINC). Lower plasma chemokine levels as well as decreased amylasemia, hematocrit and plasma interleukin-1beta (Il-1beta) levels were found either in mild or severe AP treated with Dex. Pancreatic neutrophil infiltration was attenuated by Dex in mild but not in severe AP. In conclusion, by targeting MAPKs, NF-kappaB and STAT3 pathways, Dex treatment down-regulated the chemokine expression in different cell sources during mild and severe AP, resulting in decreased severity of the disease.

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.

Expression of nitric oxide synthase isoforms and nitric oxide production in acute pancreatitis and associated lung injury

BACKGROUND/AIMS

The role of nitric oxide (NO) has been increasingly implicated in the pathophysiology of acute pancreatitis (AP). Studies have shown increased NO production in AP although not all are agreeable on whether NO is beneficial or detrimental in AP. This study aims to profile NO production and NO synthase (NOS) expression in the pancreas and lungs in the progression of AP in mice to gain insights to the role played by different NOS isoforms.

METHODS

AP was induced in mice by hourly administration of cerulein. NO production was determined by measuring the total nitrite and nitrate (NOx) content while NOS expression was measured by Western blot.

RESULTS

Pancreatic NO production increased sharply and was sustained throughout AP. iNOS expression was greatly increased while eNOS was downregulated at the later stages. In the lungs, there was an unexpected early increase in the constitutive NOS expression; however iNOS was also significantly overexpressed at the later time point along with a significant increase in NO. Acinar cells were found to overproduce NO in response to cerulein hyperstimulation with iNOS again being the major contributor.

CONCLUSION

These data show that NO production and NOS expression are differentially regulated temporally and in magnitude in the pancreas and lungs in response to cerulein hyperstimulation which suggests differing roles for each NOS isoform. and IAP.

The role of redox status on chemokine expression in acute pancreatitis

This study focused on the involvement of oxidative stress in the mechanisms mediating chemokine production in different cell sources during mild and severe acute pancreatitis (AP) induced by bile-pancreatic duct obstruction (BPDO) and 3.5% NaTc, respectively. N-Acetylcysteine (NAC) was used as antioxidant treatment. Pancreatic glutathione depletion, acinar overexpression of monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant (CINC), and activation of p38MAPK, NF-kappaB and STAT3 were found in both AP models. NAC reduced the depletion of glutathione in BPDO- but not in NaTc-induced AP, in which oxidative stress overwhelmed the antioxidant capability of NAC. As a result, inhibition of the acinar chemokine expression and signalling pathways occurs in mild, but not in severe AP. However, MCP-1 and CINC expressions in whole pancreas and plasma chemokine levels were not reduced by NAC, even in BPDO-induced AP, suggesting that in addition to acini, other pancreatic cells produced chemokines by antioxidant resistant mechanisms. The high Il-6 plasma levels found during AP, both in NAC-treated and non-treated rats, pointed out cytokines as activating factors of chemokine expression in non-acinar cells. In conclusion, from early AP oxidant-mediated MAPK, NF-kappaB and STAT3 activation triggers the chemokine expression in acini but not in non-acinar cells.

Signal transduction of MCP-1 expression induced by pancreatitis-associated ascitic fluid in pancreatic acinar cells

Pancreatitis-associated ascitic fluid (PAAF) is known to contribute to the progression of acute pancreatitis (AP). We have investigated the capability of PAAF to activate the expression of MCP-1 in pancreatic acinar cells and the involvement of MAPK, NF-kappaB and STAT3 as downstream signalling transduction pathways. The actions of dexamethasone (Dx) and N-acetylcysteine (NAC) on the PAAF's acinar effects have also been evaluated. Acinar cells were incubated for 1 hr with PAAF collected from rats with severe AP induced by sodium taurocholate in the absence or presence of Dx (10(-7) M) or NAC (30 mM). MCP-1 mRNA expression, phospho-p38-MAPK, IkappaB alpha, nuclear p65 levels and nuclear translocation of STAT3 were analysed. In response to PAAF, overexpression of MCP-1, phosphorylation of p38-MAPK, degradation of IkappaB alpha and increases in p65 nuclear levels and STAT3 activity were found in acinar cells. PAAF-mediated MCP-1 up-regulation was completely suppressed by Dx and NAC. MAPK activation was only inhibited by NAC, NF-kappaB activation was repressed by Dx and NAC, and STAT3 pathway was strongly blocked by Dx and significantly reduced by NAC. In conclusion, acinar cells were activated by PAAF to produce MCP-1, mainly via NF-kappaB and STAT3 pathways. Both downstream pathways were targeted by Dx and NAC to repress the PAAF-mediated acinar MCP-1 up-regulation.

Signal transduction of MCP-1 expression induced by pancreatitis-associated ascitic fluid in pancreatic acinar cells

Pancreatitis-associated ascitic fluid (PAAF) is known to contribute to the progression of acute pancreatitis (AP). We have investigated the capability of PAAF to activate the expression of MCP-1 in pancreatic acinar cells and the involvement of MAPK, NF-κB and STAT3 as downstream signalling transduction pathways. The actions of dexamethasone (Dx) and N-acetylcysteine (NAC) on the PAAF’s acinar effects have also been evaluated. Acinar cells were incubated for 1 hr with PAAF collected from rats with severe AP induced by sodium taurocholate in the absence or presence of Dx (10⁻⁷ M) or NAC (30 mM). MCP-1 mRNA expression, phospho-p38-MAPK, IκBα, nuclear p65 levels and nuclear translocation of STAT3 were analysed. In response to PAAF, overexpression of MCP-1, phosphorylation of p38-MAPK, degradation of IκBα and increases in p65 nuclear levels and STAT3 activity were found in acinar cells. PAAF-mediated MCP-1 up-regulation was completely suppressed by Dx and NAC. MAPK activation was only inhibited by NAC, NF-κB activation was repressed by Dx and NAC, and STAT3 pathway was strongly blocked by Dx and significantly reduced by NAC. In conclusion, acinar cells were activated by PAAF to produce MCP-1, mainly via NF-κB and STAT3 pathways. Both downstream pathways were targeted by Dx and NAC to repress the PAAF-mediated acinar MCP-1 up-regulation.

Role of substance P and bradykinin in acute pancreatitis induced by secretory phospholipase A2

OBJECTIVES

Secretory phospholipases A2 (sPLA2s) induce acute pancreatitis when injected into the common bile duct of rats. Substance P via neurokinin 1 (NK-1) receptors and bradykinin via B2 receptors are described to play important roles in the pathophysiology of acute pancreatitis. This study was undertaken to evaluate the role of substance P and bradykinin in the sPLA2-induced pancreatitis.

METHODS

Rats were submitted to the common bile duct injection of sPLA2 obtained from Naja mocambique mocambique venom at 300 microg/kg. At 4 hours thereafter, measurement of pancreatic plasma extravasation, pancreatic and lung myeloperoxidase (MPO), serum amylase, and serum tumor necrosis factor alpha levels were evaluated.

RESULTS

Injection of sPLA2 significantly increased all parameters evaluated. Pretreatment with either the NK-1 receptor antagonist SR140333 or the B2 receptor antagonist icatibant largely reduced the increased pancreatic plasma extravasation and circulating levels of tumor necrosis factor alpha. Both treatments partly reduced the MPO levels in the pancreas, whereas in the lungs, icatibant was more efficient to reduce the increased MPO levels. In addition, icatibant largely reduced the serum levels of amylase, whereas SR140333 had no significant effect.

CONCLUSIONS

We concluded that NK-1 and B2 receptors can regulate important steps in the local and remote inflammation during acute pancreatitis induced by sPLA2.

Pharmacological approach to acute pancreatitis

The aim of the present review is to summarize the current knowledge regarding pharmacological prevention and treatment of acute pancreatitis (AP) based on experimental animal models and clinical trials. Somatostatin (SS) and octreotide inhibit the exocrine production of pancreatic enzymes and may be useful as prophylaxis against Post Endoscopic retrograde cholangiopancreatography Pancreatitis (PEP). The protease inhibitor Gabexate mesilate (GM) is used routinely as treatment to AP in some countries, but randomized clinical trials and a meta-analysis do not support this practice. Nitroglycerin (NGL) is a nitrogen oxide (NO) donor, which relaxes the sphincter of Oddi. Studies show conflicting results when applied prior to ERCP and a large multicenter randomized study is warranted. Steroids administered as prophylaxis against PEP has been validated without effect in several randomized trials. The non-steroidal anti-inflammatory drugs (NSAID) indomethacin and diclofenac have in randomized studies showed potential as prophylaxis against PEP. Interleukin 10 (IL-10) is a cytokine with anti-inflammatory properties but two trials testing IL-10 as prophylaxis to PEP have returned conflicting results. Antibodies against tumor necrosis factor-alpha (TNF-α) have a potential as rescue therapy but no clinical trials are currently being conducted. The antibiotics beta-lactams and quinolones reduce mortality when necrosis is present in pancreas and may also reduce incidence of infected necrosis. Evidence based pharmacological treatment of AP is limited and studies on the effect of potent anti-inflammatory drugs are warranted.

Pharmacologic disruption of TRPV1-expressing primary sensory neurons but not genetic deletion of TRPV1 protects mice against pancreatitis

OBJECTIVES

Transient receptor potential subtype vanilloid 1 (TRPV1) is an ion channel that is primarily expressed by primary sensory neurons where it mediates pain and heat sensation and participates in neurogenic inflammation. In this study, we examined the role of TRPV1 during neurogenic activation of pancreatic inflammation using a secretagogue-induced model in mice.

METHODS

A supramaximal dose of caerulein (50 microg/kg) was injected hourly for 12 hours. Mice lacking TRPV1 were compared to wild-type animals.

RESULTS

All the parameters: serum amylase, pancreatic myeloperoxidase activity, histological scoring, pancreatic wet weight/body weight ratio, and quantification of neurokinin-1 receptor internalization indicated that null mice were not protected from acute pancreatitis. However, when primary sensory neurons were ablated by injection of the neurotoxin and TRPV1 agonist, resiniferatoxin, pancreatitis was ameliorated in wild-type mice but not in null mice, indicating that nerves bearing TRPV1 are part of the inflammatory pathway in acute pancreatitis because disappearance significantly reduced the inflammatory response.

CONCLUSIONS

Nerves expressing TRPV1 participate in the neurogenic inflammation during acute pancreatitis. The lack of protection in TRPV1 null mice suggests that an alternate pathway to TRPV1 coexists in the same neurons.

The inflammatory cascade in acute pancreatitis: relevance to clinical disease

Acute pancreatitis is an inflammatory condition that is initiated by the intra pancreatic activation of proteases. Pancreatic enzyme activation triggers a local and systemic inflammatory response that is associated with recruitment of inflammatory cells into the pancreas and a widespread up-regulation of inflammatory markers in distant tissues.

Extrapancreatic organ impairment during acute pancreatitis induced by bile-pancreatic duct obstruction. Effect of N-acetylcysteine

Multiple organ failure is frequently associated with acute pancreatitis (AP). Our aim was to study pulmonary, hepatic and renal complications developed in the course of AP experimentally induced in rats by bile-pancreatic duct obstruction (BPDO), differentiating the complications caused by AP itself, from those directly caused by bile duct obstruction (BDO), after ligating the choledocus. N-acetylcysteine (NAC) was administered as a therapeutic approach. Myeloperoxidase activity revealed neutrophil infiltration in lungs from 12 h after BDO, even if AP was not triggered. Lactate dehydrogenase (LDH) activity indicated hepatocyte death from 48 h after BDO, and from 24 h following BPDO-induced AP onwards, an effect delayed until 48 h by NAC treatment. Rats with single cholestasis (BDO) and rats with BPDO-induced AP showed a significant increase in plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT) and bilirubin concentration from 12 h onwards, whose values were reduced by NAC treatment at early BPDO. No renal failure was found during 120 h of bile-pancreatic obstruction. Our results showed lung and liver impairment as a result of BDO, even if AP does not develop. Pancreatic damage and extrapancreatic complications during AP induced by BPDO were palliated by NAC treatment.

Angiotensin II type 1 receptor-dependent nuclear factor-kappaB activation-mediated proinflammatory actions in a rat model of obstructive acute pancreatitis

Angiotensin II is a key mediator of inflammation, and nuclear factor-kappaB (NF-kappaB) plays a critical role in various inflammatory diseases, including acute pancreatitis (AP). This study sought to elucidate the mechanism mediating angiotensin II involvement in angiotensin II type 1 (AT1) receptor-mediated NF-kappaB activation, and ultimately in proinflammatory actions of AP pathogenesis. A rat model of obstructive pancreatitis was induced by ligation of the common biliopancreatic duct. Pancreatic injury was determined by assessing pancreatic histology, myeloperoxidase activity, and serum interleukin-6. Protein levels of pancreatic angiotensinogen and AT1 receptor as well as NF-kappaB inhibitory subunits (IkappaBalpha and IkappaBbeta) and phospho-NF-kappaB p65, kappaB-related proteins (intercellular adhesion molecule-1, cyclooxygenase-2, and interleukin-1), and NADPH oxidase isoforms p67 and p22 were examined by Western blot. Nuclear kappaB binding activity and degree of oxidative stress were determined by electrophoretic mobility shift assay and glutathione/nitrotyrosine examination, respectively. The effects of losartan, an AT1 receptor antagonist, on NF-kappaB-mediated proinflammatory actions were also assessed. Induction of AP was associated with a time-dependent increase in pancreatic angiotensinogen levels. AT1 receptor blockade with losartan improved the pancreatic histological damage, myeloperoxidase activity, and serum interleukin-6. Losartan treatment also reduced AP-associated depletion of IkappaBbeta and elevation of phospho-NF-kappaB p65 protein expression as well as the enhanced nuclear kappaB binding activity and elevated levels of kappaB-related proteins. In addition, losartan treatment suppressed pancreatic glutathione and nitrotyrosine levels, which were consistent with decreased NADPH oxidase expression. These data provide substantial evidence that angiotensin II is involved in AT1 receptor-mediated NADPH oxidase-dependent NF-kappaB activation; thus, it might ultimately promote proinflammatory actions during AP pathogenesis.

Redox-sensitive modulation of CD45 expression in pancreatic acinar cells during acute pancreatitis

CD45, a transmembrane protein tyrosine phosphatase required for signal transduction in leukocytes, has recently been found in pancreatic acinar cells. We have investigated the relationship between kinetic expression of CD45 on acinar cells during acute pancreatitis (AP) and the ability of these cells to produce tumour necrosis factor-alpha (TNF-alpha) through mechanisms sensitive to the cellular redox state. Flow cytometric analysis showed a significant decrease in the constitutive expression of CD45 in acinar cells from six hours onwards after inducing AP by bile-pancreatic duct obstruction (BPDO) in parallel with a significant increase in acinar TNF-alpha production. Changes in protein expression on the acinar cell surface preceded CD45 mRNA down-regulation, which was not found until 12 hours after BPDO. N-Acetylcysteine treatment delayed and reduced the down-regulation of CD45 expression induced by AP and prevented acinar cells from producing TNF-alpha. Our results show that CD45 expression is down-regulated in acinar cells during acute pancreatitis by redox-sensitive mechanisms, and they support the notion that CD45 negatively controls the production of cytokines in pancreatic acinar cells.

Role of tumor necrosis factor-alpha in acute pancreatitis: from biological basis to clinical evidence

Tumor necrosis factor (TNF)-alpha is a pleiotropic cytokine that exerts host-damaging effects in different autoimmune and inflammatory diseases. It is a key regulator of other proinflammatory cytokines and of leukocyte adhesion molecules, and it is a priming activator of immune cells. In recent years, several research lines-mostly derived from animal models and in vitro studies-suggested that TNF-alpha plays a pivotal role in the pathogenesis of acute pancreatitis. In particular, it contributes to the systemic progression of the inflammatory response and to the end-organ dysfunction often observed in severe disease. Current clinical applications of TNF-alpha in acute pancreatitis include the assessment of blood concentrations to predict disease severity and to identify individuals prone to develop complications such as multiple organ failure and septic shock. However, TNF-alpha is rapidly cleared from the bloodstream, and sensitivity and overall accuracy of its measurement seem strictly time dependent, thereby being of potential prognostic value only in the first days after the onset of the disease. In parallel, TNF-alpha has been evaluated as a novel pharmacologic target for treating pancreatitis. Although promising results have been observed in the laboratory, transition to clinical practice seems problematic, in particular, in the light of divergent results obtained in sepsis trials. Therefore, in future clinical trials pertaining to TNF-alpha neutralization in acute pancreatitis, timing of intervention should be related to changes in TNF-alpha serum levels, and inclusion and exclusion criteria should be accurately selected to better define the population most likely to benefit.