Multidrug strategies are effective in the treatment of severe experimental pancreatitis

Hemorheological and Microcirculatory Relations of Acute Pancreatitis

Acute pancreatitis still means a serious challenge in clinical practice. Its pathomechanism is complex and has yet to be fully elucidated. Rheological properties of blood play an important role in tissue perfusion and show non-specific changes in acute pancreatitis. An increase in blood and plasma viscosity, impairment of red blood cell deformability, and enhanced red blood cell aggregation caused by metabolic, inflammatory, free radical-related changes and mechanical stress contribute to the deterioration of the blood flow in the large vessels and also in the microcirculation. Revealing the significance of these changes in acute pancreatitis may better explain the pathogenesis and optimize the therapy. In this review, we give an overview of the role of impaired microcirculation by changes in hemorheological properties in acute pancreatitis.

Release of endogenous hydrogen sulfide in enteric nerve cells suppresses intestinal motility during severe acute pancreatitis

Previous studies have shown that during severe acute pancreatitis (SAP) attacks, hydrogen sulfide (H2S) is released in the colon. However, the roles played by H2S in regulating enteric nerves remain unclear. In this study, we examined the association between SAP-induced H2S release and loss of intestinal motility, and also explored the relevant mechanism in enteric nerve cells. A rat SAP model was constructed and enteric nerve cells were prepared. Intestinal mobility was evaluated by measuring the number of bowel movements at indicated time points and by performing intestinal propulsion tests. The production of inflammatory cytokines during a SAP attack was quantified by ELISA, and the levels of cystathionine-γ-lyase (CSE) and cystathionine-β-synthase (CBS) were examined by immunohistochemistry and western blot analysis. In vivo studies showed that PI3K/Akt/Sp1 signaling in enteric nerve cells was blocked, confirming the mechanism of endogenous H2S formation by western blot analysis and immunofluorescence. Our results also showed that rats with SAP symptoms had reduced intestinal motility. Furthermore, PI3K/Akt/Sp1 signaling was triggered and CSE expression was up-regulated, and these changes were associated with H2S formation in the colon. In addition, propargylglycine reduced the levels of inflammatory cytokines and suppressed the release of H2S. Enteric nerve cells that were incubated with LY294002 and transfected with a Sp1-knockdown vector displayed decreased levels of CSE production, which led to a decrease in H2S production. These results suggest that SAP symptoms suppressed the intestinal motility of rats via the release of H2S in enteric nerve cells, which was dependent on the inflammation-induced PI3K/Akt/Sp1 signaling pathway.

Change in biliary motility in rats with severe acute pancreatitis and its effect

AIM: To observe the change in biliary motility in rats with severe acute pancreatitis and study its effect.

METHODS: Severe acute pancreatitis was induced in 28 male Sprague-Dawley rats by injection of sodium taurocholate into the pancreatobiliary duct. These rats were randomly divided into an experiment group (n = 14) and a control group (n = 14). Another 14 male SD rats injected with saline served as a sham operation group (SO group, n = 14). The experiment group was pretreated by intraperitoneal injection of anisodamine at 20 mg/kg. The control group was pretreated with saline. Twenty-four hours after operation, quantitative ^99mTc-EHIDA hepatobiliary dynamic imaging was performed in each group. Plasma levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and endotoxin (ET) were detected, and the levels of cholecystokinin 8 (CCK8) in plasma, gallbladder and duodenal tissues were also measured. Abdominal viscera bacterial translocation rates were compared among these groups.

RESULTS: In comparison with the SO group and experiment group, a significant delay in duodenal appearance time (DAT) was noted in the control group (56.73 s ± 12.34 s vs 48.44 s ± 11.12 s, 29.52 s ± 11.83 s). A lower level of CCK8 in duodenal tissue was found in the control group than in the SO group and experiment group (5.24 pg/mL ± 0.56 pg/mL vs 5.81 pg/mL ± 0.45 pg/mL, 6.25 pg/mL ± 0.53 pg/mL). The levels of TNF-α, IL-1β, and ET were significantly higher in the control group and experiment group at 24 h after operation than in the SO group (P < 0.05 for all). The levels of TNF-α and ET were significantly lower in the experiment group than in the control group (ET: 0.148 EU/mL ± 0.032 EU/mL vs 0.320 EU/mL ± 0026 EU/mL, P = 0.040; TNF-α: 89.24 pg/mL ± 34.45 pg/mL vs 123.18 pg/mL ± 41.24 pg/mL, P = 0.049). The abdominal viscera bacterial translocation rate was significantly higher in the control group than in the other two groups (0.714% vs 0.573%, 0.143%, P < 0.05).

CONCLUSION: The inhibition of biliary motility was observed in rats with acute pancreatitis, and the change in biliary motility may promote viscera bacterial translocation.

Circulating nucleosomes as predictive markers of severe acute pancreatitis

Background

The components of nucleosomes, which contain DNA and histones, are released into the circulation from damaged cells and can promote inflammation. We studied whether the on-admission levels of circulating nucleosomes predict the development of severe acute pancreatitis (AP), in particular among the patients who present without clinical signs of organ dysfunction.

Methods

This is a prospective study of 74 AP patients admitted to Helsinki University Hospital from 2003 to 2007. Twenty-three patients had mild, 27 moderately severe, and 24 severe AP as defined by the revised Atlanta criteria. 14/24 severe AP patients had no sign of organ dysfunction on admission (modified marshall score <2). Blood samples were obtained on admission and the plasma levels of nucleosomes were measured using enzyme-linked immunosorbent assay.

Results

The on-admission levels of nucleosomes were significantly higher in severe AP than in mild or moderately severe AP (p < 0.001 for all), higher in non-survivors (n = 8) than in survivors (p = 0.019), and correlated with the on-admission levels of C-reactive protein (p < 0.001) and creatinine (p < 0.001). Among the AP patients who presented without organ dysfunction, the on-admission nucleosome level was an independent predictor of severe AP (p = 0.038, gender-adjusted forward-stepping logistic regression).

Conclusions

Circulating nucleosome levels may be helpful in identifying, on admission to hospital, the AP patients who present without clinical signs of organ dysfunction, and, yet, are bound to develop organ dysfunction during hospitalization.

Metaflammatory responses during obesity: Pathomechanism and treatment

Obesity induced inflammation acts as a reflex produced due to altered metabolic homeostasis in accordance to the nutrient overload on the metabolic cells. It involves up-regulation of the genes encoding for cytokines, chemokines and other inflammatory mediators through activated transcription factors - nuclear factor-kB, activator protein-1, nuclear factor of activated T cells and signal transducer and activator of transcription 3. These execute macromolecular innate immune cell sensor - inflammasome to activate caspase-1 pathway resulting in proteolytic maturation. Secretion of pro-inflammatory cytokines including TNF-α, IL-6, CRP, IL-1β, etc. from the M1 macrophages of white adipose tissue is increased, whereas there occurs a steep decline in the production of anti-inflammatory cytokines like IL-10, IL-Ra, adiponectin. Not only the adipose tissue, but also the immune cells, liver, brain, muscles and pancreas suffers from the inflammatory insult during obese condition and are exaggeratedly affected. The inflammatory kinases like JNK and IKK apart from inhibiting insulin action and glucose uptake, down-regulate transcriptional process resulting in increased expression of pro-inflammatory cytokines. Macrophage-like Kupffer cells initiate the inflammatory process in the liver preceding the inflammatory signals produced by the white adipose tissue which may further lead to hepatic-necro-inflammation. The muscle-fibre is affected by the cytokines and therefore results in decreased glycogen synthesis. The triggered hypothalamic-pituitary-adrenal axis further affects the expression of inflammatory cytokines thus altering insulin homeostasis and initiating glucose intolerance. Anti-inflammatory treatment so as to curb the severity of inflammatory responses includes administration of synthetic drugs to target the actual inflammatory molecules and various therapeutic interventions.

Protective effects of polyenoylphosphatidylcholine in rats with severe acute pancreatitis

OBJECTIVE

The aim of this study was to investigate the protective effect of polyenoylphosphatidylcholine (PPC) in rats with severe acute pancreatitis (SAP) and its mechanism.

METHODS

Seventy-two clean, conventional Sprague-Dawley rats were randomly divided into 4 groups (SAP; sham operation [SO], SAP + PPC, and SO + PPC; n = 18 per group). The SAP model was induced by injecting 4% sodium taurocholate (1 mL/kg) into the biliopancreatic duct. Animals in the SO groups underwent laparotomy and biliopancreatic duct puncture without fluid injection. Polyenoylphosphatidylcholine (50 mg/kg) was injected through the penis dorsal vein. Pancreatic acinar cell membrane fluidity and pancreatic tissue calcium pump activity were measured through fluorescence polarization and quantization of phosphonium ions, whereas pancreatic tissue superoxide dismutase and malondialdehyde were detected through xanthine oxidase method and thiobarbituric acid colorimetric analysis method, respectively.

RESULTS

The SAP + PPC group had significantly improved pathologic pancreas; increased in pancreatic acinar cell membrane fluidity, pancreatic tissue Ca-Mg-ATPase activity, and superoxide dismutase; as well as decreased in malondialdehyde, ascites volume, and serum amylase compared with the SAP group.

CONCLUSIONS

Polyenoylphosphatidylcholine could reduce the damage to the pancreas through increasing pancreatic acinar cell membrane fluidity and pancreatic tissue calcium pump activity. Polyenoylphosphatidylcholine also scavenges oxygen free radicals and reduces lipid peroxide levels.

Inflammatory profiling of early experimental necrotizing pancreatitis

AIMS

Inflammatory mediators play a pivotal role in severe necrotizing pancreatitis (SNP). Therapeutic approaches aim at the early inflammatory liberation of cytokines to avoid systemic complications. The present study evaluates the kinetics of inflammatory mediator release in SNP.

MAIN METHODS

Experimental SNP was induced in male Wistar rats using the GDOC model. The animals were allocated into seven groups (n = 6/group). In group 1, sample harvesting was performed after sham operation while in groups 2-7 this was performed 1 h, 2 h, 4 h, 6 h, 9 h, and 12 h after initiation of SNP, respectively. Inflammatory mediator release,morphologic injury, and tissue MPO concentrations were evaluated between 1 and 12 h after induction.

KEY FINDINGS

Pancreatic injury showed a continuous increase over the observation period (p b 0.05, respectively). MPO levels in the pancreas and lungs increased until 12 h after induction (p b 0.05, respectively). Antiinflammatory IL-10 showed an early peak and the pro-inflammatory mediators TNFα and IL-1β peaked after 6 and 9 h, respectively (p b 0.05, respectively). HMGB1 levels constantly increased over time (p b 0.05, respectively).

SIGNIFICANCE

The present study shows the release of relevant pro- and anti-inflammatory mediators in SNP for the first time in one single experimental setup. Inflammatory mediators peak within the first few hours after SNP induction. Consequently, the effect of therapeutic approaches on early changes in cytokine release should be evaluated later than 2 h after initiation.

Immunomodulatory therapies for acute pancreatitis

It is currently difficult for conventional treatments of acute pancreatitis (AP), which primarily consist of anti-inflammatory therapies, to prevent the progression of AP or to improve its outcome. This may be because the occurrence and progression of AP, which involves various inflammatory cells and cytokines, includes a series of complex immune events. Considering the complex immune system alterations during the course of AP, it is necessary to monitor the indicators related to immune cells and inflammatory mediators and to develop more individualized interventions for AP patients using immunomodulatory therapy. This review discusses the recent advances in immunomodulatory therapies. It has been suggested that overactive inflammatory responses should be inhibited and excessive immunosuppression should be avoided in the early stages of AP. The optimal duration of anti-inflammatory therapy may be shorter than previously expected (< 24 h), and appropriate immunostimulatory therapies should be administered during the period from the 3^rd d to the 14^th d in the course of AP. A combination therapy of anti-inflammatory and immune-stimulating drugs would hopefully constitute an alternative to anti-inflammatory drug monotherapy. Additionally, the detection of the genotypes of critical inflammatory mediators may be useful for screening populations of AP patients at high risk of severe infections to enable the administration of early interventions to improve their prognosis.

Recent advances on plasmin inhibitors for the treatment of fibrinolysis-related disorders

Growing evidence suggests that plasmin is involved in a number of physiological processes in addition to its key role in fibrin cleavage. Plasmin inhibition is critical in preventing adverse consequences arising from plasmin overactivity, e.g., blood loss that may follow cardiac surgery. Aprotinin was widely used as an antifibrinolytic drug before its discontinuation in 2008. Tranexamic acid and ε-aminocaproic acid, two small molecule plasmin inhibitors, are currently used in the clinic. Several molecules have been designed utilizing covalent, but reversible, chemistry relying on reactive cyclohexanones, nitrile warheads, and reactive aldehyde peptidomimetics. Other major classes of plasmin inhibitors include the cyclic peptidomimetics and polypeptides of the Kunitz and Kazal-type. Allosteric inhibitors of plasmin have also been designed including small molecule lysine analogs that bind to plasmin's kringle domain(s) and sulfated glycosaminoglycan mimetics that bind to plasmin's catalytic domain. Plasmin inhibitors have also been explored for resolving other disease states including cell metastasis, cell proliferation, angiogenesis, and embryo implantation. This review highlights functional and structural aspects of plasmin inhibitors with the goal of advancing their design.

From nitric oxide to hyperbaric oxygen: invisible and subtle but nonnegligible gaseous signaling molecules in acute pancreatitis

Nitric oxide (NO), carbon monoxide, and hydrogen sulfide in addition to hydrogen are well established as gaseous signal molecules throughout the body. Although the role of gasotransmitters in acute pancreatitis (AP) has been explored for many years, many details remain to be elucidated. The physiologic effect of NO in AP mainly relies on induced NO synthase, which stimulates the production of cytokines in the blood. Carbon monoxide inhibits nuclear factor-κB activation, which leads to amelioration of the inflammatory response. Hydrogen sulfide displays a dual role in the mechanism of AP according to its concentration in the system. Hydrogen is a newly discovered gaseous signaling molecule, and currently, there is little evidence that it has any function in alleviating inflammation. We discovered that hyperbaric oxygen is a novel gasotransmitter that has potential use in the treatment of AP. The correlation among hyperbaric oxygen, hypoxia inducible factor 1α, and other signaling pathways should be further studied. We also discuss some prospects and issues that remain to be resolved in this review. In summary, the discovery of gaseous signal molecules has established a new platform for deep investigation of the mechanism of AP, and our knowledge of the role of gasotransmitters in AP will increase with further research.

Pharmacological cholinergic stimulation as a therapeutic tool in experimental necrotizing pancreatitis

OBJECTIVES

The endogenous immune response is influenced by the stimulation of the vagal nerve. Stimulation or ablation has a direct impact on the release of pro- and anti-inflammatory mediators. In the progression of acute pancreatitis from local to systemic disease, these mediators play a pivotal role. This study evaluates the effect of pharmacologic stimulation of the cholinergic system on pancreatic damage in experimental necrotizing pancreatitis.

METHODS

Experimental severe necrotizing pancreatitis was induced in male Wistar rats using the glycodeoxycholic acid model. Animals with acute pancreatitis (n = 6) were compared with animals with acute pancreatitis and prophylactic or therapeutic pharmacologic activation of the cholinergic system using nicotine, physostigmine, or neostigmine (n = 36). Twelve hours after the induction of acute pancreatitis, morphological damage as well as the myeloperoxidase levels of the pancreas and the serum levels of high-mobility group box 1 protein were evaluated.

RESULTS

Prophylactic and delayed therapeutic application of nicotine, physostigmine, or neostigmine significantly attenuated the severity of acute pancreatitis 12 hours after the induction of severe necrotizing pancreatitis compared with untreated controls as evaluated with histological scores, myeloperoxidase, and high-mobility group box 1 levels (P < 0.05).

CONCLUSIONS

Stimulation of the cholinergic system is useful to attenuate damage in experimental acute pancreatitis. Not only prophylactic but also delayed application was effective in the present study.

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

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

N-acetylcysteine ameliorates severe acute pancreatitis-associated intestinal injury in rats

AIM: To investigate the effects of treatment with n-acetylcysteine (NAC) on plasma levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-10 and ICAM1 expression in small intestine tissue in rats with severe acute pancreatitis (SAP) and to explore the possible mechanisms involved.

METHODS: Seventy Wistar rats were randomly divided into a sham operation group (SO, n = 24), a SAP group (n = 24) and a NAC treatment group (n = 24). SAP was induced in rats by injecting 5.0% sodium taurocholate into the biliary-pancreatic duct. Rats in the SO group were given an infusion of normal saline instead. Rats in the NAC group underwent SAP induction and were given an intraperitoneal injection of NAC 1 hour before the operation, and rats in the SO group and SAP group were given an intraperitoneal injection of normal saline. Eight rats were sacrificed 6, 12 or 24 h after operation in each group. Plasma levels of amylase (AMY), endotoxin, diamine oxidase (DAO), D-lactic acid, TNF-α, IL-1β and IL-10 were measured. Pathologic changes in the small intestine were observed and scored. ICAM1 mRNA and protein expression in the small intestine was tested by real-time PCR and Western blot, respectively.

RESULTS: Compared to the SAP group, plasma levels of AMY, TNF-α and IL-β were significantly lower at all three time points (all P < 0.05) and serum levels of endotoxin, DAO and D- lactic acid were significantly lower at 12 and 24 h (both P < 0.05) in the NAC group. Serum levels of IL-10 in the NAC group were increased compared to the SAP group at all three time points. The pathology score of the small intestinal was significantly lower in the NAC group than the SAP group at 12 and 24 h. Although the mRNA expression of ICAM1 was increased at each time point in the SAP group compared with the SO group, it was significantly decreased in the NAC group compared with the SAP group (6 h: 1.13 ± 0.28 vs 2.37 ± 0.63; 12 h: 1.27 ± 0.34 vs 2.94 ± 0.82; 24 h: 1.19 ± 0.26 vs 2.68 ± 0.95; all P < 0.05). The protein expression of ICAM1 had the same trend as the mRNA expression between the NAC and SAP groups (6 h: 0.74 ± 0.11 vs 1.04 ± 0.25; 12 h: 0.88 ± 0.17 vs 1.25 ± 0.33; 24 h: 0.75 ± 0.13 vs 1.18 ± 0.22; all P < 0.05).

CONCLUSION: Administration of NAC ameliorates severe acute pancreatitis-associated intestinal injury in rats possibly by regulating plasma levels of TNF-α, IL-1β and IL-10 and inhibiting ICAM1 expression in the small intestine.

The clinical course of acute pancreatitis and the inflammatory mediators that drive it

Acute pancreatitis (AP) is a common emergency condition. In the majority of cases, it presents in a mild and self-limited form. However, about 20% of patients develop severe disease with local pancreatic complications (including necrosis, abscess, or pseudocysts), systemic organ dysfunction, or both. A modern classification of AP severity has recently been proposed based on the factors that are causally associated with severity of AP. These factors are both local (peripancreatic necrosis) and systemic (organ failure). In AP, inflammation is initiated by intracellular activation of pancreatic proenzymes and/or nuclear factor-κB. Activated leukocytes infiltrate into and around the pancreas and play a central role in determining AP severity. Inflammatory reaction is first local, but may amplify leading to systemic overwhelming production of inflammatory mediators and early organ failure. Concomitantly, anti-inflammatory cytokines and specific cytokine inhibitors are produced. This anti-inflammatory reaction may overcompensate and inhibit the immune response, rendering the host at risk for systemic infection. Currently, there is no specific treatment for AP. However, there are several early supportive treatments and interventions which are beneficial. Also, increasing the understanding of the pathogenesis of systemic inflammation and the development of organ dysfunction may provide us with future treatment modalities.