Induction Of Acute Pancreatitis Research Articles

Protective Effect of Pretreatment with Acenocoumarol in Cerulein-Induced Acute Pancreatitis.

Coagulation is recognized as a key player in inflammatory and autoimmune diseases. The aim of the current research was to examine the effect of pretreatment with acenocoumarol on the development of acute pancreatitis (AP) evoked by cerulein. Methods: AP was induced in rats by cerulein administered intraperitoneally. Acenocoumarol (50, 100 or 150 µg/kg/dose/day) or saline were given once daily for seven days before AP induction. Results: In rats with AP, pretreatment with acenocoumarol administered at the dose of 50 or 100 µg/kg/dose/day improved pancreatic histology, reducing the degree of edema and inflammatory infiltration, and vacuolization of acinar cells. Moreover, pretreatment with acenocoumarol given at the dose of 50 or 100 µg/kg/dose/day reduced the AP-evoked increase in pancreatic weight, serum activity of amylase and lipase, and serum concentration of pro-inflammatory interleukin-1β, as well as ameliorated pancreatic DNA synthesis and pancreatic blood flow. In contrast, acenocoumarol given at the dose of 150 μg/kg/dose did not exhibit any protective effect against cerulein-induced pancreatitis. Conclusion: Low doses of acenocoumarol, given before induction of AP by cerulein, inhibit the development of that inflammation.

Prophylactic Administration of Silybin Ameliorates L-Arginine-Induced Acute Pancreatitis.

BackgroundOxidative stress have been shown to play a role in the pathogenesis of acute pancreatitis. The aim of this study was to investigate the potential effect of silybin, a potent antioxidant, on L-arginine-induced acute pancreatitis in an experimental rat model.Material/MethodsForty female Wistar Albino rats were divided into 5 groups as follows: Group 1 (C): control group (n=8), Group 2 (SL): silybin group (n=8), Group 3 (LA): acute pancreatitis group (n=8), Group 4 (SLLA): prophylaxis group (n=8), and Group 5 (LASL): treatment group (n=8). Group C (control) received 2 intraperitoneal (i.p.) injections of physiological saline at an interval of 1 h. Group SL received only a single i.p. injection of silybin. The SLLA group received a single i.p. injection of silybin before the induction of acute pancreatitis with L-arginine, whereas the LASL group received the same injection after the induction of acute pancreatitis with L-arginine. Pancreatic tissues were histopathologically examined. Levels of amylase and oxidative stress markers (total oxidant status and total anti-oxidant status) were determined in the blood samples. Oxidative stress index was calculated.ResultsIn comparison to the LA, the prophylaxis and treatment groups showed significant improvements in serum oxidative stress parameters (p=0.001 and p=0.005, respectively). Histopathological analysis showed that the treatment group had significant improvements in edema scores only (p=0.006), whereas the prophylaxis group had the same improvements in inflammation and necrosis scores as well as in total scores (p=0.004, 0.006, and 0.004, respectively).ConclusionsWhen used for prophylactic rather than therapeutic purposes, silybin ameliorates serum oxidative stress parameters and improves histopathological results via its antioxidant and anti-inflammatory properties.

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

ABSTRACTPurpose/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.

Dynamic landscape of pancreatic carcinogenesis reveals early molecular networks of malignancy

ObjectiveThe initial steps of pancreatic regeneration versus carcinogenesis are insufficiently understood. Although a combination of oncogenic Kras and inflammation has been shown to induce malignancy, molecular networks of early carcinogenesis...

Hydrogen sulphide exacerbates acute pancreatitis by over-activating autophagy via AMPK/mTOR pathway.

Previously, we have shown that hydrogen sulphide (H2S) might be pro‐inflammatory during acute pancreatitis (AP) through inhibiting apoptosis and subsequently favouring a predominance of necrosis over apoptosis. In this study, we sought to investigate the detrimental effects of H2S during AP specifically with regard to its regulation on the impaired autophagy. The incubated levels of H2S were artificially intervened by an administration of sodium hydrosulphide (NaHS) or DL‐propargylglycine (PAG) after AP induction. Accumulation of autophagic vacuoles and pre‐mature activation of trypsinogen within acini, which indicate the impairment of autophagy during AP, were both exacerbated by treatment with NaHS but attenuated by treatment with PAG. The regulation that H2S exerted on the impaired autophagy during AP was further attributed to over‐activation of autophagy rather than hampered autophagosome–lysosome fusion. To elucidate the molecular mechanism that underlies H2S‐mediated over‐activation of autophagy during AP, we evaluated phosphorylations of AMP‐activated protein kinase (AMPK), AKT and mammalian target of rapamycin (mTOR). Furthermore, Compound C (CC) was introduced to determine the involvement of mTOR signalling by evaluating phosphorylations of downstream effecters including p70 S6 kinase (P70S6k) and UNC‐51‐Like kinase 1 (ULK1). Our findings suggested that H2S exacerbated taurocholate‐induced AP by over‐activating autophagy via activation of AMPK and subsequently, inhibition of mTOR. Thus, an active suppression of H2S to restore over‐activated autophagy might be a promising therapeutic approach against AP‐related injuries.

Tissue-specific regulation of potassium homeostasis by high doses of cationic amino acids.

The administration of l-arginine hydrochloride has been used for testing pituitary secretion in humans, and as an experimental model for induction of acute pancreatitis in rats and mice. Whereas in the first case, the administration of the amino acid is associated with hiperkalemia, in the model of acute pancreatitis no data are available on possible changes in potassium homeostasis. The present study shows that the acute administration to mice of l-arginine hydrochloride or other cationic amino acids almost duplicate plasma potassium levels. This effect was associated to a marked decrease of tissue potassium in both pancreas and liver. No changes were found in other tissues. These changes cannot be ascribed to the large load of chloride ions, since similar effects were produced when l-ornithine aspartate was administered. The changes in potassium levels were dependent on the dose. The displacement of intracellular potassium from the liver and pancreas to the extracellular compartment appears to be dependent on the entry of the cationic amino acid, since the administration of an equivalent dose of alfa-difluoromethyl ornithine HCl (DFMO), a non physiological analog of l-ornithine, which is poorly taken by the tissues in comparison with the physiological cationic amino acids, did not produce any change in potassium levels in pancreas and liver. The analyses of the expression of cationic amino acid transporters (CAT) suggest that the CAT-2 transporter may be implicated in the potassium/cationic amino acid interchange in liver and pancreas. The possible physiological or pathological relevance of these findings is discussed.

Cathelicidin-related antimicrobial peptide modulates the severity of acute pancreatitis in mice.

The present study aimed to investigate the immunomodulatory effects of mouse cathelicidin-related antimicrobial peptide (CRAMP) on experimental acute pancreatitis (AP). AP is a common clinical condition characterized by acute abdominal inflammation. Innate immune cells and mediators are intrinsically linked to the pathogenesis of AP. Cathelicidins are innate immunity-derived antimicrobial peptides that exert immunomodulatory effects on various host cells. However, how cathelicidins are involved and modulate the severity and inflammatory responses of AP remains unclear. In the present study, the mouse CRAMP gene-deficient cnlp−/− mice and their wild-type C57BL/6J littermates were induced with AP by multiple hourly injections of supramaximal doses of caerulein. Serum amylase levels, pancreatic myeloperoxidase activity and histological examination were performed in order to determine the disease severity and the levels of inflammatory cytokines. Disease severity and inflammatory markers were subsequently evaluated in the control mice, cnlp−/− C57BL/6J mice with AP, and wild-type C57BL/6J mice with AP. The results demonstrated that cnlp−/− mice exhibited a more severe phenotype and inflammatory response following AP induction compared with the wild-type mice, as evidenced by increased serum amylase levels, pancreatic myeloperoxidase release, and early inflammatory mediator tumor necrosis factor-α production. Histological examination confirmed that CRAMP deficiency worsened the pancreatic inflammatory condition. These results indicate that CRAMP may be considered a novel modulatory mediator in mouse experimental AP.

Methylene blue attenuates mitochondrial dysfunction of rat kidney during experimental acute pancreatitis.

The disturbance of mitochondrial functions has been considered as one of the mechanisms of pathogenesis of acute pancreatitis (AP) followed by kidney failure. This study was aimed to investigate the effects of methylene blue (MB) on pancreas and kidney mitochondrial respiratory functions during experimental acute pancreatitis in rats. AP was induced by administrating sodium taurocholate into the pancreatic duct of male Wistar rats. The rats were divided into three groups: the MB group, MB (5 mg/kg) was injected intravenously 10 min prior to AP induction; the AP group, saline solution was injected intravenously 10 min prior to AP induction; and the sham operation group, isotonic sodium chlorine was used instead of sodium taurocholate. The animals were sacrificed after 24 h. The pancreas and kidney were removed for mitochondrial assay by oxygraphic and spectrophotometric methods. Intravenous injection of MB did not prevent AP-induced inhibition of pancreatic mitochondrial respiration; however, MB significantly improved kidney mitochondrial respiratory functions with complex I-dependent substrates glutamate and malate. The activity of complex I of mitochondria isolated from AP-damaged kidney was increased after pretreatment with MB. However, MB did not affect AP-inhibited kidney mitochondrial respiration with succinate. MB had no protective effects on amylase activity or on urea content in serum in AP. The disturbances of kidney mitochondrial energy metabolism in experimental model of severe AP can be ameliorated by MB administration.

Characterization and Predictive Value of Near Infrared 2-Deoxyglucose Optical Imaging in Severe Acute Pancreatitis.

BackgroundStudying the uptake of 2-deoxy glucose (2-DG) analogs such as 2-Deoxy-2-[18F] fluoroglucose (FDG) is a common approach to identify and monitor malignancies and more recently chronic inflammation. While pancreatitis is a common cause for false positive results in human studies on pancreatic cancer using FDG, the relevance of these findings to acute pancreatitis (AP) is unknown. FDG has a short half-life. Thus, with an aim to accurately characterize the metabolic demand of the pancreas during AP in real-time, we studied the uptake of the non-radioactive, near infrared fluorescence labelled 2-deoxyglucose analog, IRDye® 800CW 2-DG probe (NIR 2-DG; Li-Cor) during mild and severe biliary AP.MethodsWistar rats (300 g; 8–12/group) were administered NIR 2-DG (10 nM; I.V.). Mild and severe biliary AP were respectively induced by biliopancreatic duct ligation (DL) alone or along with infusing glyceryl trilinoleate (GTL; 50 μL/100 g) within 10 minutes of giving NIR 2-DG. Controls (CON) only received NIR 2-DG. Imaging was done every 5–10 minutes over 3 hrs. Average Radiant Efficiency [p/s/cm²/sr]/[μW/cm²] was measured over the pancreas using the IVIS 200 in-vivo imaging system (PerkinElmer) using the Living Image® software and verified in ex vivo pancreata. Blood amylase, lipase and pancreatic edema, necrosis were measured over the course of AP.ResultsNIR 2-DG uptake over the first hour was not influenced by AP induction. However, while the signal declined in controls and rats with mild AP, there was significantly higher retention of NIR 2-DG in the pancreas after 1 hour in those with GTL pancreatitis. The increase was > 3 fold over controls in the GTL group and was verified to be in the pancreas ex vivo. In vitro, pancreatic acini exposed to GTL had a similar increase in NIR 2-DG uptake which was followed by progressively worse acinar necrosis. Greater retention of NIR 2-DG in vivo was associated with worse pancreatic necrosis, reduced ATP concentrations and mortality, which were not predicted by the blood parameters.ConclusionIn-vivo fluorescent imaging of a non-radioactive near infrared 2-DG optical probe can predict the AP severity early during the disease.

Reduced Pancreatic Exocrine Function and Organellar Disarray in a Canine Model of Acute Pancreatitis.

The aim of the present study was to investigate the pancreatic exocrine function in a canine model and to analyze the changes in organelles of pancreatic acinar cells during the early stage of acute pancreatitis (AP). AP was induced by retrograde injection of 5% sodium taurocholate (0.5 ml/kg) into the main pancreatic duct of dogs. The induction of AP resulted in serum hyperamylasemia and a marked reduction of amylase activity in the pancreatic fluid (PF). The pancreatic exocrine function was markedly decreased in subjects with AP compared with the control group. After the induction of AP, histological examination showed acinar cell edema, cytoplasmic vacuolization, fibroblasts infiltration, and inflammatory cell infiltration in the interstitium. Electron micrographs after the induction of AP revealed that most of the rough endoplasmic reticulum (RER) were dilated and that some of the ribosomes were no longer located on the RER. The mitochondria were swollen, with shortened and broken cristae. The present study demonstrated, in a canine model, a reduced volume of PF secretion with decreased enzyme secretion during the early stage of AP. Injury of mitochondria and dilatation and degranulation of RER may be responsible for the reduced exocrine function in AP. Furthermore, the present model and results may be useful for researching novel therapeutic measures in AP.

Ameliorative Effects of Curcumin on Fibrinogen-Like Protein-2 Gene Expression, Some Oxido-Inflammatory and Apoptotic Markers in a Rat Model of l-Arginine-Induced Acute Pancreatitis.

The aim of the study was to investigate the ameliorative effects of curcumin on fibrinogen like protein-2 (fgl-2), some oxido-inflammatory and apoptotic markers in rat-induced acute pancreatitis (AP). Seventy-five albino rats were divided into control group, l-arginine (l-Arg)-induced AP group, curcumin pre-treated group before AP induction, curcumin post-treated group after AP induction, and curcumin injected group only. AP group showed severe necrotizing pancreatitis confirmed by histopathological changes and elevations in serum amylase and lipase activities, levels of epithelial neutrophil-activating peptide 78, tissue content of protein carbonyls, levels of tumor necrosis factor α, and caspase-3 as well as myeloperoxidase activity. Significant elevation in pancreatic fgl-2 mRNA expression was detected in AP group. Improvement of all parameters was detected with increase of caspase-3 in both curcumin-treated groups that confirmed curcumin ameliorative effects against AP through induction of apoptosis and inhibition of micro-thrombosis, inflammation, and oxidative stress.

Therapeutic effects of quercetin on early inflammation in hypertriglyceridemia-related acute pancreatitis and its mechanism.

To investigate the therapeutic effects of quercetin on early-stage inflammation in hypertriglyceridemia (HTG)-related acute pancreatitis (AP) both invivo and invitro, and its possible mechanism. Invivo, rats were fed a high-fat diet to induce HTG, and AP was induced by intraperitoneal injection of cerulein (50μg/kg×2). Quercetin (100, 150 and 200mg/kg) was administered by intraperitoneal injection after AP induction. Invitro, rat exocrine acinar cells were preincubated with palmitic acid (PA, 0.1mmol/L, 6h) with quercetin (5, 10, 20 and 40μM) prior to a cholecystokinin analog CCK-8 (20pM). Injury of the pancreas was assessed by amylase secretion and pancreatic histological evaluation. Inflammation was estimated by measuring IL-1β, IL-6, TNFα and NF-kB expression. Dynamic expression of IRE1α, sXBP1, C/EBPα and C/EBPβ was monitored by real-time PCR, immunofluorescence (IF) and western blot (WB). Quercetin intervention reduced plasma amylase level (P<0.001) in a dose-dependent manner, attenuated pancreatic histopathological damage (P<0.05), and reduced the mRNA and protein expression of NF-kB, IL-1β, IL-6, TNFα (P<0.05) more significantly in HTG-related AP rats than in normal-lipid AP rats. Quercetin also down-regulated gene and protein expression levels of IRE1α, sXBP1, C/EBPα and C/EBPβ in a dose-dependent manner. Quercetin attenuates early-stage inflammation in HTG-related AP, probably by reducing IRE1α, sXBP1, C/EBPα and C/EBPβ expression.

The Role of Eugenol in the Prevention of Acute Pancreatitis-Induced Acute Kidney Injury: Experimental Study.

Aim. Acute pancreatitis is an inflammatory intra-abdominal disease, which takes a severe form in 15–20% of patients and can result in high mortality especially when complicated by acute renal failure. The aim of this study is to assess the possible reduction in the extent of acute kidney injury after administration of eugenol in an experimental model of acute pancreatitis. Materials and Methods. 106 male Wistar rats weighing 220–350 g were divided into 3 groups: (1) Sham, with sham surgery; (2) Control, with induction of acute pancreatitis, through ligation of the biliopancreatic duct; and (3) Eugenol, with induction of acute pancreatitis and eugenol administration at a dose of 15 mg/kg. Serum urea and creatinine, histopathological changes, TNF-α, IL-6, and MPO activity in the kidneys were evaluated at predetermined time intervals. Results. The group that was administered eugenol showed milder histopathological changes than the Control group, TNF-α activity was milder in the Eugenol group, and there was no difference in activity for MPO and IL-6. Serum urea and creatinine levels were lower in the Eugenol group than in the Control group. Conclusions. Eugenol administration was protective for the kidneys in an experimental model of acute pancreatitis in rats.

Effect of Previous High Glutamine Infusion on Inflammatory Mediators and Mortality in an Acute Pancreatitis Model.

Parenteral glutamine supplementation in acute inflammatory conditions is controversial. We evaluated the inflammatory and survival responses after parenteral glutamine infusion in sodium taurocholate-induced acute pancreatitis (AP) model. Lewis rats received 1 g/kg parenteral glutamine (n = 42), saline (n = 44), or no treatment (n = 45) for 48 h before AP induction. Blood, lung, and liver samples were collected 2, 12, and 24 h after AP to measure serum cytokines levels and tissue heat shock protein (HSP) expression. From each group, 20 animals were not sacrificed after AP for a 7-day mortality study. Serum cytokine levels did not differ among groups at any time point, but the intragroup analysis over time showed higher interferon-γ only in the nontreatment and saline groups at 2 h (versus 12 and 24 h; both p ≤ 0.05). The glutamine group exhibited greater lung and liver HSP90 expression than did the nontreatment group at 2 and 12 h, respectively; greater liver HSP90 and HSP70 expression than did the saline group at 12 h; and smaller lung HSP70 and liver HSP90 expression than did the nontreatment group at 24 h (all p ≤ 0.019). The 7-day mortality rate did not differ among groups. In experimental AP, pretreatment with parenteral glutamine was safe and improved early inflammatory mediator profiles without affecting mortality.

Effects of Tocilizumab on Experimental Severe Acute Pancreatitis and Associated Acute Lung Injury.

To examine the therapeutic effects of tocilizumab, an antibody against interleukin-6 receptor, on experimental severe acute pancreatitis and associated acute lung injury. The optimal dose of tocilizumab and the activation of interleukin-6 inflammatory signaling were also investigated. Randomized experiment. Research laboratory at a university hospital. Experimental severe acute pancreatitis in rats. Severe acute pancreatitis was induced by retrograde injection of sodium taurocholate (50 mg/kg) into the biliopancreatic duct. In dose-study, rats were administered with different doses of tocilizumab (1, 2, 4, 8, and 16 mg/kg) through the tail vein after severe acute pancreatitis induction. In safety-study, rats without severe acute pancreatitis induction were treated with high doses of tocilizumab (8, 16, 32, and 64 mg/kg). Serum and tissue samples of rats in time-study were collected for biomolecular and histologic evaluations at different time points (2, 6, 12, 18, and 24 hr). 1) Under the administration of tocilizumab, histopathological scores of pancreas and lung were decreased, and severity parameters related to severe acute pancreatitis and associated lung injury, including serum amylase, C-reactive protein, lung surfactant protein level, and myeloperoxidase activity, were all significant alleviated in rat models. 2) Dose-study demonstrated that 2 mg/kg tocilizumab was the optimal treatment dose. 3) Basing on multi-organ pathologic evaluation, physiological and biochemical data, no adverse effect and toxicity of tocilizumab were observed in safety-study. 4) Pancreatic nuclear factor-κB and signal transducer and activator of transcription 3 were deactivated, and the serum chemokine (C-X-C motif) ligand 1 was down-regulated after tocilizumab administration. Our study demonstrated tocilizumab, as a marketed drug commonly used for immune-mediated diseases, was safe and effective for the treatment of experimental severe acute pancreatitis and associated acute lung injury. Our findings provide experimental evidences for potential clinical application of tocilizumab in severe acute pancreatitis and associated complications.

Apigenin Attenuates Inflammation in Experimentally Induced Acute Pancreatitis-Associated Lung Injury

ABSTRACTBackground: Acute pancreatitis is associated with acute lung injury. The aim of the present study is to evaluate alterations of lungs in an experimental model of acute pancreatitis (AP) following both bilio-pancreatic duct obstruction close to the duodenum. Acute pancreatitis is a common disease with significant mortality. This situation makes the need of finding protective factors for the lung parenchyma, imperative. In the present study there is an effort to clarify the role of apigenin, a substance which is well known for its antioxidant and anti-inflammatory effects, on lung injury, following acute pancreatitis in rats. Materials and methods: In the present study, 126 male Wistar-type rats 3–4 months old and 220–350 g weight were used. At time 0 we randomly assigned the following groups: Group Sham: Rats were subjected to virtual surgery. Group Control: Rats were subjected to surgery for induction of acute pancreatitis. Group Apigenin: Rats were subjected to surgery for induction of acute pancreatitis and enteral feeding with apigenin. Immunochemistry for TNF-α and IL-6 as well as MPO activity were measured at predetermined time intervals 6, 12, 24, 48, and 72 h, in order to evaluate architectural disturbances of the lung tissue. Results: From the pathological reports we realized that comparing the control group with the apigenin group, there is an improvement of lung tissue damage following apigenin administration, with statistical significance. Apigenin reduces most histopathological alterations of the pulmonary tissue, reduces MPO and TNF-α activity at 48 hours and, furthermore, reduces IL-6 activity at 72 hours post-administration. Conclusions: Oral Apigenin administration in rats, following experimental induced acute pancreatitis, seems to be protective on the lung tissue. Apigenin administration to humans could potentially ameliorate acute lung injuries. However, special caution is required for humans' use, as more detailed studies are needed.

Role of YAP and TAZ in pancreatic ductal adenocarcinoma and in stellate cells associated with cancer and chronic pancreatitis.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a fibrotic and inflammatory microenvironment that is formed primarily by activated, myofibroblast-like, stellate cells. Although the stellate cells are thought to contribute to tumorigenesis, metastasis and drug resistance of PDAC, the signaling events involved in activation of the stellate cells are not well defined. Functioning as transcription co-factors, Yes-associated protein (YAP) and its homolog transcriptional co-activator with PDZ-binding motif (TAZ) modulate the expression of genes involved in various aspects of cellular functions, such as proliferation and mobility. Using human tissues we show that YAP and TAZ expression is restricted to the centroacinar and ductal cells of normal pancreas, but is elevated in cancer cells. In particular, YAP and TAZ are expressed at high levels in the activated stellate cells of both chronic pancreatitis and PDAC patients as well as in the islets of Langerhans in chronic pancreatitis tissues. Of note, YAP is up regulated in both acinar and ductal cells following induction of acute and chronic pancreatitis in mice. These findings indicate that YAP and TAZ may play a critical role in modulating pancreatic tissue regeneration, neoplastic transformation, and stellate cell functions in both PDAC and pancreatitis.

Apoptotic Mechanisms of Peroxisome Proliferator-Activated Receptor-γ Activation in Acinar Cells During Acute Pancreatitis.

ObjectiveThe objective of this study was to determine the mechanism by which activation of peroxisome proliferator–activated receptor-γ promotes apoptosis of acinar cells in pancreatitis.MethodsAR42j cells pretreated with the peroxisome proliferator–activated receptor-γ agonist pioglitazone were activated by cerulein as an in vitro model of acute pancreatitis. Inflammatory cytokines and amylase were detected by enzyme-linked immunosorbent assay. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell apoptosis was measured by flow cytometry and terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling staining. Activity of caspases was determined. Bax and Bcl-2 levels were assayed by Western blot.ResultsCytokines, amylase, and cellular proliferation decreased in pioglitazone-pretreated cells. Pioglitazone increased the activity of caspases 3, 8, and 9 in cerulein-activated AR42j cells as well as in the pancreas of rats 3 hours after induction of severe acute pancreatitis. Acinar cell apoptosis was induced by reducing the mitochondrial membrane potential in the pioglitazone group. Pioglitazone increased expression of proapoptotic Bax proteins and decreased antiapoptotic Bcl-2 in cerulein-induced AR42j cells and decreased Bcl-2 levels in pancreatic tissue of severe acute pancreatitis rats 1 and 3 hours after induction.ConclusionPioglitazone may promote apoptosis of acinar cells through both intrinsic and extrinsic apoptotic pathways in acute pancreatitis.

FTY720 Attenuates Acute Pancreatitis in Hypertriglyceridemic Apolipoprotein CIII Transgenic Mice.

Hypertriglyceridemic pancreatitis (HTGP) is often encountered clinically as a common form of recurrent acute pancreatitis (AP). It is important to evaluate the management of severe hypertriglyceridemia (HTG) or anti-inflammation in the prophylaxis of HTGP in the clinic. FTY720 (2-amino-2[2-(4-octylphenyl) ethyl]-1, 3-propanediol) is a new anti-inflammatory agent with low toxicity and reported to ameliorate lung injury with pancreatitis in rat. We evaluated its protective affection on AP induced by seven hourly intraperitoneal injection of cerulein in apolipoprotein CIII transgenic mice with severe HTG. FTY720 at 1.5 mg/kg was administered by gastric lavage daily for 3 days before induction of AP. The effects of FTY720 to protect against HTGP were assessed by serum amylase, pancreatic pathological scores, immunostaining, and the expression of inflammatory cytokine genes. As a result, injection of cerulein resulted in more severe pathological changes of AP and higher monocyte chemoattractant protein 1 expression in the pancreas in transgenic than in nontransgenic mice. FTY720 pretreatment improved the pathological severity of AP and decreased the expression of monocyte chemoattractant protein 1 in the pancreas significantly, especially near fourfold reduction in transgenic mice. However, FTY720 did not affect plasma triglyceride levels, and other inflammatory factors and plasma amylase were not correlated with the extent of pancreatic damage in AP with or without FTY720 administration. In summary, our study in a new model, apolipoprotein CIII transgenic mice, demonstrated that HTG mice are susceptible to induction of AP. Prophylactic treatment of FTY720 can significantly attenuate cerulein-induced AP and hence warrant further investigation of sphingosine-1-phosphate receptors agonist for potential clinical application in recurrent attacks of HTGP.

PP12 - γ-Glutamyl cysteine modulates the inflammatory response via protein phosphatases

Acute pancreatitis (AP) is an acute inflammatory process of the pancreatic gland that may lead to severe systemic complications. Cytokines and oxidative stress play a role in the early pathophysiological events of the disease. Previous studies have shown the antioxidant properties of γ-glutamyl cysteine (γ–GC), a metabolic precursor for the synthesis of glutathione. C57BL/6 mice were treated with cerulein (7 injections each with 50 μg/kg bw). To evaluate the effects of γ-GC, a group of mice with AP was treated with γ-GC (75 mg/kg bw) administered in two doses at 4 and 7 hours after the first cerulein injection. Plasma lipase activity was measured and histological studies were performed to confirm the induction of AP. The aim of this work was to assess the role of γ-GC in the modulation of the inflammatory response and oxidative stress in AP. The activity of pancreatic lipase in plasma increased after induction of acute pancreatitis, but this increase was lower with γ-GC treatment. The histopathological study showed that the inflammatory process and tissue edema were reduced with the γ-GC treatment. The increase in pancreatic myeloperoxydase activity and TNF-α mRNA levels were abrogated in mice treated with γ-GC after AP induction. Moreover, the c-Jun N-terminal kinase (JNK) pathway activation was blocked upon γ-GC treatment. On the contrary, protein levels of protein tyrosine phosphatases SHP-1, SHP-2 and protein serine threonine phosphatase PP2A, which were reduced upon AP induction, were recovered after γ-GC administration. Redox pairs, such as reduced glutathione/oxidized glutathione, and cysteine/cystine were not affected by the γ-GC treatment. In conclusion, our results show the anti-inflammatory properties of the γ-GC in AP, which seem to be mediated by recovering protein phosphatase levels and avoiding the activation of the JNK pathway, independently of the redox thiol status.