Experimental Severe Acute Pancreatitis Research Articles

Bufalin alleviates inflammatory response and oxidative stress in experimental severe acute pancreatitis through activating Keap1-Nrf2/HO-1 and inhibiting NF-κB pathways

Severe acute pancreatitis (SAP) is a prevalent acute inflammatory disease that is clinically manifested by systemic inflammation dysregulation, resulting in a significantly elevated mortality rate. Bufalin has been verified to have potent pharmacological properties, including analgesic, anti-tumor and anti-inflammatory effects. However, it remains unclear whether bufalin inhibits SAP. Thus, we aim to explore the impact of bufalin in SAP rats and to evaluate the potential mechanisms of action. In addition to analyzing serum biochemistry and pancreatic tissue pathology, we elucidated its mechanisms of action through enzyme-linked immunosorbent assay (ELISA), immunohistochemical analysis, Western blot, and quantitative real-time PCR. The results demonstrated that bufalin dose-dependently reversed the elevation of serum Amylase (Amy) and Lipase (LPS) levels in SAP rats, alleviating pancreatic tissue pathological damage. Bufalin exhibited potent antioxidant effects by reducing malondialdehyde (MDA) levels, decreasing Superoxide dismutase (SOD) and glutathione(GSH) consumption, inhibiting the interaction of Keap1-Nrf2, and increasing HO-1 expression. Furthermore, bufalin inhibited TNF-α, IL-6, IL-1β, p-NF-κB-p65, p-IκBα, and NF-κB-p65 expression, while enhancing IκBα expression, ultimately confirming its anti-inflammatory effects on SAP. In summary, our findings suggest that bufalin exerts anti-inflammatory and antioxidant actions in NaT-SAP rats by inhibiting NF-κB and activating the Keap1-Nrf2/HO-1 pathway. This study represents the inaugural application of bufalin in NaT-induced SAP rats, indicating its potential as an effective therapeutic agent for SAP patients.

Leucine-rich repeat kinase 2 promotes the development of experimental severe acute pancreatitis.

Translocation of gut bacteria into the pancreas promotes the development of severe acute pancreatitis (SAP). Recent clinical studies have also highlighted the association between fungal infections and SAP. The sensing of gut bacteria by pattern recognition receptors promotes the development of SAP via the production of proinflammatory cytokines; however, the mechanism by which gut fungi mediate SAP remains largely unknown. Leucine-rich repeat kinase 2 (LRRK2) is a multifunctional protein that regulates innate immunity against fungi via Dectin-1 activation. Here, we investigated the role of LRRK2 in SAP development and observed that administration of LRRK2 inhibitors attenuated SAP development. The degree of SAP was greater in Lrrk2 transgenic (Tg) mice than in control mice and was accompanied by an increased production of nuclear factor-kappaB-dependent proinflammatory cytokines. Ablation of the fungal mycobiome by anti-fungal drugs inhibited SAP development in Lrrk2 Tg mice, whereas the degree of SAP was comparable in Lrrk2 Tg mice with or without gut sterilization by a broad range of antibiotics. Pancreatic mononuclear cells from Lrrk2 Tg mice produced large amounts of IL-6 and TNF-α upon stimulation with Dectin-1 ligands, and inhibition of the Dectin-1 pathway by a spleen tyrosine kinase inhibitor protected Lrrk2 Tg mice from SAP. These data indicate that LRRK2 activation is involved in the development of SAP through proinflammatory cytokine responses upon fungal exposure.

Dimethyl trisulphide alleviates the severity of experimental acute pancreatitis through acinar cytoprotection

Dimethyl trisulphide alleviates the severity of experimental acute pancreatitis through acinar cytoprotection

Xanthohumol alleviates oxidative stress and impaired autophagy in experimental severe acute pancreatitis through inhibition of AKT/mTOR.

Severe acute pancreatitis (SAP) is a lethal gastrointestinal disorder, yet no specific and effective treatment is available. Its pathogenesis involves inflammatory cascade, oxidative stress, and autophagy dysfunction. Xanthohumol (Xn) displays various medicinal properties, including anti-inflammation, antioxidative, and enhancing autophagic flux. However, it is unclear whether Xn inhibits SAP. This study investigated the efficacy of Xn on sodium taurocholate (NaT)-induced SAP (NaT-SAP) in vitro and in vivo. First, Xn attenuated biochemical and histopathological responses in NaT-SAP mice. And Xn reduced NaT-induced necrosis, inflammation, oxidative stress, and autophagy impairment. The mTOR activator MHY1485 and the AKT activator SC79 partly reversed the treatment effect of Xn. Overall, this is an innovative study to identify that Xn improved pancreatic injury by enhancing autophagic flux via inhibition of AKT/mTOR. Xn is expected to become a novel SAP therapeutic agent.

Нейтрофільні позаклітинні пастки як терапевтична мішень при системних ускладненнях гострого панкреатиту

The review focuses on the role of neutrophilic extracellular traps (NETs) in systemic complications of acute pancreatitis. NETs can activate trypsin, cause inflammation and pancreatic tissue damage, and clog the excretory ducts. The main fatal complications of acute pancreatitis, such as acute lung injury, kidney, myocardial and CNS damage, intestinal dysfunction, hemocoagulation disorders are associated with NETs. Focusing on the formation and degradation of NETs may be a way to develop strategies for treating organ damage in severe acute pancreatitis. Current data on the use of NET-targeted therapy in experimental severe acute pancreatitis, which is aimed at blocking the NETs formation and disassembly of the DNA scaffold, inhibition of proteins toxicity in NETs, are considered.

Fentanyl but Not Morphine or Buprenorphine Improves the Severity of Necrotizing Acute Pancreatitis in Rats.

Opioids are widely used for the pain management of acute pancreatitis (AP), but their impact on disease progression is unclear. Therefore, our aim was to study the effects of clinically relevant opioids on the severity of experimental AP. Various doses of fentanyl, morphine, or buprenorphine were administered as pre- and/or post-treatments in rats. Necrotizing AP was induced by the intraperitoneal injection of L-ornithine-HCl or intra-ductal injection of Na-taurocholate, while intraperitoneal caerulein administration caused edematous AP. Disease severity was determined by laboratory and histological measurements. Mu opioid receptor (MOR) expression and function was assessed in control and AP animals. MOR was expressed in both the pancreas and brain. The pancreatic expression and function of MOR were reduced in AP. Fentanyl post-treatment reduced necrotizing AP severity, whereas pre-treatment exacerbated it. Fentanyl did not affect the outcome of edematous AP. Morphine decreased vacuolization in edematous AP, while buprenorphine pre-treatment increased pancreatic edema during AP. The overall effects of morphine on disease severity were negligible. In conclusion, the type, dosing, administration route, and timing of opioid treatment can influence the effects of opioids on AP severity. Fentanyl post-treatment proved to be beneficial in AP. Clinical studies are needed to determine which opioids are best in AP.

Pretreatment with chitosan oligosaccharides attenuate experimental severe acute pancreatitis via inhibiting oxidative stress and modulating intestinal homeostasis.

Severe acute pancreatitis (SAP) is a severe acute abdominal disease. Recent evidence shows that intestinal homeostasis is essential for the management of acute pancreatitis. Chitosan oligosaccharides (COS) possess antioxidant activity that are effective in treating various inflammatory diseases. In this study we explored the potential therapeutic effects of COS on SAP and underlying mechanisms. Mice were treated with COS (200 mg·kg-1·d-1, po) for 4 weeks, then SAP was induced in the mice by intraperitoneal injection of caerulein. We found that COS administration significantly alleviated the severity of SAP: the serum amylase and lipase levels as well as pancreatic myeloperoxidase activity were significantly reduced. COS administration suppressed the production of proinflammatory cytokines (TNF-α, IL-1β, CXCL2 and MCP1) in the pancreas and ileums. Moreover, COS administration decreased pancreatic inflammatory infiltration and oxidative stress in SAP mice, accompanied by activated Nrf2/HO-1 and inhibited TLR4/NF-κB and MAPK pathways. We further demonstrated that COS administration restored SAP-associated ileal damage and barrier dysfunction. In addition, gut microbiome analyses revealed that the beneficial effect of COS administration was associated with its ability to improve the pancreatitis-associated gut microbiota dysbiosis; in particular, probiotics Akkermansia were markedly increased, while pathogenic bacteria Escherichia-Shigella and Enterococcus were almost eliminated. The study demonstrates that COS administration remarkably attenuates SAP by reducing oxidative stress and restoring intestinal homeostasis, suggesting that COS might be a promising prebiotic agent for the treatment of SAP.

Knockout of the Mitochondrial Calcium Uniporter Strongly Suppresses Stimulus-Metabolism Coupling in Pancreatic Acinar Cells but Does Not Reduce Severity of Experimental Acute Pancreatitis.

Acute pancreatitis is a frequent disease that lacks specific drug treatment. Unravelling the molecular mechanisms of acute pancreatitis is essential for the development of new therapeutics. Several inducers of acute pancreatitis trigger sustained Ca2+ increases in the cytosol and mitochondria of pancreatic acinar cells. The mitochondrial calcium uniporter (MCU) mediates mitochondrial Ca2+ uptake that regulates bioenergetics and plays an important role in cell survival, damage and death. Aberrant Ca2+ signaling and mitochondrial damage in pancreatic acinar cells have been implicated in the initiation of acute pancreatitis. The primary aim of this study was to assess the involvement of the MCU in experimental acute pancreatitis. We found that pancreatic acinar cells from MCU−/− mice display dramatically reduced mitochondrial Ca2+ uptake. This is consistent with the drastic changes of stimulus-metabolism coupling, manifested by the reduction of mitochondrial NADH/FAD+ responses to cholecystokinin and in the decrease of cholecystokinin-stimulated oxygen consumption. However, in three experimental models of acute pancreatitis (induced by caerulein, taurolithocholic acid 3-sulfate or palmitoleic acid plus ethanol), MCU knockout failed to reduce the biochemical and histological changes characterizing the severity of local and systemic damage. A possible explanation of this surprising finding is the redundancy of damaging mechanisms activated by the inducers of acute pancreatitis.

Dexmedetomidine attenuates inflammation and pancreatic injury in a rat model of experimental severe acute pancreatitis via cholinergic anti-inflammatory pathway.

BackgroundExcessive inflammatory responses play a critical role in the development of severe acute pancreatitis (SAP), and controlling such inflammation is vital for managing this often fatal disease. Dexmedetomidine has been reported to possess protective properties in inflammatory diseases. Therefore, this study aimed to investigate whether dexmedetomidine pre-treatment exerts an anti-inflammatory effect in rats with SAP induced by sodium taurocholate, and if so, to determine the potential mechanism.MethodsSAP was induced with sodium taurocholate. Rats received an intraperitoneal injection of dexmedetomidine 30 min before sodium taurocholate administration. α-bungarotoxin, a selective alpha-7 nicotinic acetylcholine receptor (α7nAchR) antagonist, was injected intra-peritoneally 30 min before dexmedetomidine administration. The role of the vagus nerve was evaluated by performing unilateral cervical vagotomy before the administration of dexmedetomidine. Efferent discharge of the vagal nerve was recorded by the BL-420F Data Acquisition & Analysis System. Six hours after onset, serum pro-inflammatory cytokine (tumor necrosis factor α [TNF-α] and interleukin 6 [IL-6]) levels and amylase levels were determined using an enzyme-linked immunosorbent assay and an automated biochemical analyzer, respectively. Histopathological changes in the pancreas were observed after hematoxylin and eosin staining and scored according to Schmidt criteria.ResultsPre-treatment with dexmedetomidine significantly decreased serum levels of TNF-α, IL-6, and amylase, strongly alleviating pathological pancreatic injury in the rat model of SAP (TNF-α: 174.2 ± 30.2 vs. 256.1±42.4 pg/ml; IL-6: 293.3 ± 46.8 vs. 421.7 ± 48.3 pg/ml; amylase: 2102.3 ± 165.3 vs. 3186.4 ± 245.2 U/L). However, the anti-inflammatory and pancreatic protective effects were abolished after vagotomy or pre-administration of α-bungarotoxin. Dexmedetomidine also significantly increased the discharge frequency and amplitude of the cervical vagus nerve in the SAP rat model (discharge frequency: 456.8 ± 50.3 vs. 332.4 ± 25.1 Hz; discharge amplitude: 33.4 ± 5.3 vs. 20.5 ± 2.9 μV).ConclusionsDexmedetomidine administration attenuated the systemic inflammatory response and local pancreatic injury caused by SAP in rats through the cholinergic anti-inflammatory pathway involving vagus- and α7nAChR-dependent mechanisms.

Macrophages-derived p38α promotes the experimental severe acute pancreatitis by regulating inflammation and autophagy

BackgroundSevere acute pancreatitis (SAP) is a common threat to human health. In the present study, we aimed to investigate the underlying mechanisms by which p38α in macrophages contributes to SAP. We used conditional knockout of p38α in macrophages and p38 MAPK inhibitors to understand the effects of p38α in macrophages on caerulein-induced inflammatory responses in SAP mice models. Methods and materialsWild-type (WT) mice were randomly divided into three groups: a control group, SAP group, and SAP + p38MAPK inhibitor (SB203580) group, and mice with a conditional knockout (KO) of p38α in macrophages were included in a KO + SAP group. We evaluated pancreatic pathology and ultra-structure by hematoxylin and eosin staining and transmission electron microscopy. The pulmonary wet-to-dry weight ratio was calculated. The serum levels of TNF-α and IL-1β were determined by ELISA. The mRNA and protein expression of inflammatory cytokines TNF-α, IL-1β, IL-17, IL-18, MIF, and MCP-1 in pancreatic tissues were tested by qRT-PCR and immunohistochemistry analysis. The protein expression of p38, caspase-1, ULK1, LC3B and p62 in pancreatic tissues was examined by Western blotting. ResultsThe results indicated that the severity of SAP as well as the expression of the cytokines TNF-α, IL-1β, IL-17, IL-18 and MCP-1 were higher in the SAP group than those in the control group, but were lower in the SAP + SB203580 and KO + SAP groups as compared with the SAP group. The protein expression of p38, caspase-1, LC3B and p62 was increased in the SAP group than that in the control group, but this result was reversed in the SAP + SB203580 and KO + SAP groups as compared with the SAP group. In addition, the ULK1 level was significantly lower in the SAP group than that in the control group, but was increased in the SAP + SB203580 and KO + SAP groups as compared with the SAP group. ConclusionsOur findings demonstrated that, macrophage derived p38α promoted the experimental severe acute pancreatitis by regulating inflammation and autophagy.

Therapeutic effect of recombinant human thrombomodulin on rat experimental severe acute pancreatitis

Therapeutic effect of recombinant human thrombomodulin on rat experimental severe acute pancreatitis

Fluid resuscitation via the rectum ameliorates hemodynamic disorders through adjusting aquaporin expression in an experimental severe acute pancreatitis model

Acute pancreatitis is an acute abdominal disease, with 10-20% of the cases deteriorating rapidly, accompanied by persistent organ failure and further development into severe acute pancreatitis (SAP). The aim of the present study was to investigate the mechanism of fluid resuscitation via the rectum in the early stages of SAP and the role of aquaporins (AQPs). An SAP model was constructed by injection of 5% sterile sodium taurocholate into the biliopancreatic duct of Sprague Dawley rats, and the mean arterial pressure (MAP) was continuously monitored via femoral artery catheterization. At 30 min after the construction of the SAP model, the rats in the fluid resuscitation groups were resuscitated with normal saline at a rate of 4 ml/kg/h through the venous or the rectal route. The AQP and Na+-K+-ATPase levels, and the correlation of the MAP and colon AQPs at the early stages of SAP were analyzed. The results demonstrated that the mRNA level of AQP-3 and AQP-4 in the distal colon decreased significantly in the group subjected to fluid resuscitation via the rectum, while no significant differences were identified in the Na+-K+-ATPase levels of the colon in that group. Furthermore, a negative correlation was identified between the expression of AQPs and the MAP (P<0.01). Thus, fluid resuscitation via the rectum appears to ameliorate hemodynamic disorders through adjusting the expression of AQP-3 and AQP-4 in the distal colon in an experimental SAP model.

Ulinastatin ameliorates tissue damage of severe acute pancreatitis through modulating regulatory T cells

BackgroundUlinastatin or urinary trypsin inhibitor (UTI) has been shown to ameliorate the inflammatory response induced by experimental severe acute pancreatitis (SAP) and hence reduce the mortality, however the mechanism of its action remains incompletely understood. We have investigated the effect of ulinastatin on regulatory T-cells (Tregs) in an established rat model of SAP.MethodsWe established a rat SAP model by injecting 5% Na-taurocholate into the pancreatic duct and treated the SAP rats with ulinastatin with different dose level (5000, 10000, 30000 U/kg) through intraperitoneal injection at 0, 6 and 12 h.ResultsWe showed that the tissue damage of pancreas and the mortality of the SAP rats were significantly reduced by ulinastatin. We also showed that in the SAP rats the frequencies of CD4+ T cells and Tregs, as well as the expressions of TGF-β1, CTLA-4, and Foxp3 were decreased in the SAP animals while IL-1β, IL-10 and TNF-α were significantly increased. Treatment with ulinastatin up-regulated the proportion of Tregs in CD4+ T cells and the expression of IL-10, Foxp3 and CTLA-4 in the SAP rats in a dose dependence fashion, while down-regulating the levels of L-1β and TNF-α, myeloperoxidase (MPO) activity.ConclusionsOur findings suggest that ulinastatin alleviates inflammatory response and tissue damage in SAP rats by increasing the proportion of Tregs. Our study provides a new mechanism for the beneficial effect of ulinastatin in SAP rat model.

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.

4-Phenylbutyric Acid Attenuates Pancreatic Beta-Cell Injury in Rats with Experimental Severe Acute Pancreatitis.

Endoplasmic reticulum (ER) stress is a particular process with an imbalance of homeostasis, which plays an important role in pancreatitis, but little is known about how ER stress is implicated in severe acute pancreatitis (SAP) induced pancreatic beta-cell injury. To investigate the effect of 4-phenylbutyric acid (4-PBA) on the beta-cell injury following SAP and the underlying mechanism, twenty-four Sprague-Dawley rats were randomly divided into sham-operation (SO) group, SAP model group, and 4-PBA treatment group. SAP model was induced by infusion of 5% sodium taurocholate into the biliopancreatic duct. 4-PBA or normal saline was injected intraperitoneally for 3 days in respective group before successful modeling. Results showed that 4-PBA attenuated the following: (1) pancreas and islet pathological injuries, (2) serum TNF-α and IL-1β, (3) serum insulin and glucose, (4) beta-cell ultrastructural changes, (5) ER stress markers (BiP, ORP150, and CHOP), Caspase-3, and insulin expression in islet. These results suggested that 4-PBA mitigates pancreatic beta-cell injury and endocrine disorder in SAP, presumably because of its role in inhibiting excessive endoplasmic reticulum stress. This may serve as a new therapeutic target for reducing pancreatic beta-cell injury and endocrine disorder in SAP upon 4-PBA treatment.

Infusion of Bone Marrow Mesenchymal Stem Cells Attenuates Experimental Severe Acute Pancreatitis in Rats.

Background & Aims. Severe acute pancreatitis (SAP) remains a high-mortality disease. Bone marrow (BM) mesenchymal stem cells (MSCs) have been demonstrated to have plasticity of transdifferentiation and to have immunomodulatory functions. In the present study, we assessed the roles of MSCs in SAP and the therapeutic effects of MSC on SAP after transplantation. Methods. A pancreatitis rat model was induced by the injection of taurocholic acid (TCA) into the pancreatic duct. After isolation and characterization of MSC from BM, MSC transplantation was conducted 24 hrs after SAP induction by tail vein injection. The survival rate was observed and MSCs were traced after transplantation. The expression of TNF-α and IL-1β mRNA in the transplantation group was also analyzed. Results. The survival rate of the transplantation group was significantly higher compared to the control group (p < 0.05). Infused MSCs were detected in the pancreas and BM 3 days after transplantation. The expression of TNF-α and IL-1β mRNA in the transplantation group was significantly lower than in the control group in both the pancreas and the lungs (p < 0.05). Conclusions. MSC transplantation could improve the prognosis of SAP rats. Engrafted MSCs have the capacity of homing, migration, and planting during the treatment of SAP.

Beneficial effects of fluid resuscitation via the rectum on hemodynamic disorders and multiple organ injuries in an experimental severe acute pancreatitis model.

Exaggerated hydration is harmful for patients with severe acute pancreatitis (SAP), and it can increase mortality rate. In this study, we investigated the role of fluid resuscitation via the rectum (FRVR) on the hemodynamic state and compared FRVR with intravenous fluid resuscitation (IVFR) on resuscitation effect and organ function in an early stage of SAP. We studied whether FRVR corrects hemodynamic disorders at an early stage of SAP in Spraque-Dawley (SD) rats and whether it mitigates organ dysfunction and whether FRVR is superior to IVFR. In both IVFR and FRVR groups, we observed a rebound in the mean arterial pressure (MAP) after 5 h and 6 h of administration (p < 0.05), respectively. MAP of the FRVR group reached the same level as the SHAM group at the end of the treatment, with hematocrit declining compared with the non-fluid resuscitation (NFR) group (p < 0.05). A concomitant increase in abdominal ascites and the lung wet/dry ratio by IVFR was depressed in the FRVR group (p < 0.05). Liver function was ameliorated in both fluid resuscitation groups (p < 0.05), consistent with histopathological improvement. TNF-α in serum and MPO in the lungs and jejunum of the FRVR group were lower than the IVFR group (p < 0.05). Pancreas histopathological injuries were ameliorated by both IVFR and FRVR (p < 0.05). Our findings suggested FRVR is a potential supplementary method for fluid management in an early stage of SAP and FRVR should be studied further.

High Phosphate Serum Levels Correlate With the Severity of Experimental Severe Acute Pancreatitis

Extracellular purines are a component of the systemic inflammatory response, and their levels are modulated by ectonucleotidases. In addition, nucleotide hydrolysis releases phosphate. We studied serum phosphate levels as a predictor of severity in acute pancreatitis (AP) and their correlation with extracellular purinergic metabolism. Acute pancreatitis was induced by the retrograde injection of sodium taurocholate. The AP group was compared with animals submitted to a model of sepsis by cecal ligation and puncture. The sham group was submitted to laparotomy and closure. We measured the phosphate and purine levels in serum and the expression of 5'-nucleotidase (CD73) and the adenosine A2a receptor in pancreatic tissue by quantitative real-time polymerase chain reaction. Serum phosphate levels were higher in severe AP and correlated with severity. Severe AP led to increased serum levels of adenosine diphosphate, adenosine monophosphate, and adenosine. In addition, adenosine monophosphate conversion to adenosine in serum was accelerated in the AP groups. We found a positive correlation between serum adenosine and phosphate in the AP groups. The expression levels of CD73 and the adenosine A2a receptor in the pancreas were not altered. Our study suggests that serum phosphate correlates with severity in AP and implicates extracellular purines in the systemic response to severe AP.

Nicotine ameliorates experimental severe acute pancreatitis via enhancing immunoregulation of CD4+ CD25+ regulatory T cells.

Activation of "nicotinic anti-inflammatory pathway" could reduce severity of inflammation and injury induced by acute pancreatitis. However, the role of regulatory T (Treg) cells in this pathway is unclear. Severe acute pancreatitis (SAP) was induced in mice through retrograde injection of 50-μL 2% Na-taurocholate into the pancreatic duct of the mouse. In nicotine treatment group, nicotine (50, 100, and 300 μg/kg) was administered 1 hour before and after SAP operation through intraperitoneal injection. We compared the properties of Treg cell percentage and specific marker such as cytotoxic T-lymphocyte antigen 4 and forkhead box transcription factor forkhead/winged helix transcription factor p3 on Treg using quantitative reverse transcription polymerase chain reaction and flow cytometry. All experiment animal serum cytokines were measured using enzyme-linked immunosorbent assay. One-way analysis of variance was applied to evaluate the experimental data and for statistical comparisons. The survival rate data were analyzed using the log-rank test. Nicotine significantly protected mice from lethal SAP in a dose-dependent fashion by inhibiting tissue injury, digestive enzyme production, and proinflammatory cytokines production. Moreover, nicotine up-regulated the number and suppressive capacity of CD4 CD25 Treg via inducing the expression of immunoregulatory molecules and transforming growth factor β1 elevation. Modulating immunoregulation of CD4 CD25 Treg is a critical mechanism for nicotinic anti-inflammatory pathway and it may be feasible to use selective agonists as an immunotherapy for SAP.

Regional arterial infusion with lipoxin A4 attenuates experimental severe acute pancreatitis.

ObjectiveInvestigate the therapeutic effect of regional arterial infusion (RAI) with Aspirin-Triggered Lipoxin A4 (ATL) in experimental severe acute pancreatitis (SAP) in rats.Materials and MethodsSAP was induced by injection of 5% sodium taurocholate into the pancreatic duct. Rats with SAP were treated with ATL (the ATL group) or physiological saline (the SAP group) infused via the left gastric artery 30 min after injection of sodium taurocholate. The sham group was subjected to the same surgical procedure, though without induction of SAP. Serum levels of amylase, phospholipase A2 (PLA2), interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were measured at 12 and 24 h after induction of SAP. Ascitic fluid, the pancreatic index (wet weight ratio) and myeloperoxidase (MPO) levels in the pancreas were determined and histopathological findings were evaluated. The expression of intercellular adhesion molecule-1 (ICAM-1), platelet endothelial cell adhesion molecule-1 (PECAM-1), NF-κB p65, and heme oxygenase-1 (HO-1) in the pancreas were estimated by immunofluorescence and western blot, respectively.ResultsATL rats had lower serum levels of TNF-α, IL-1β, and IL-6 (P<0.01), PLA2 (P<0.05), and amylase levels (P<0.05) studied as compared with the SAP group. The pancreatic index in the ATL group decreased only at 24 h as compared with the SAP group (P<0.05). The histopathological findings and MPO levels in the pancreas significantly decreased in the ATL group as compared to the SAP group (P<0.05 and P<0.01, respectively). Immunofluorescence and western blot showed that ATL attenuated the expression of NF-κB p65, ICAM-1 and PECAM-1 in the pancreas, and increased the expression of HO-1 in SAP animals.ConclusionsWe demonstrated that RAI with ATL attenuated the severity of experimental SAP, maybe achieved by improving the expression of HO-1, and down-regulating the NF-κB signaling pathway, with decreased expression of ICAM-1 and PECAM-1 and reduced generation of pro-inflammatory cytokines.