The role of tumor necrosis factor-alpha in the aggravation of cerulein-induced pancreatitis in rats

The in vivo evidence for regulated necrosis

Necrosis is a hallmark of several widespread diseases or their direct complications. In the past decade, we learned that necrosis can be a regulated process that is potentially druggable. RIPK3- and MLKL-mediated necroptosis represents by far the best studied pathway of regulated necrosis. During necroptosis, the release of damage-associated molecular patterns (DAMPs) drives a phenomenon referred to as necroinflammation, a common consequence of necrosis. However, most studies of regulated necrosis investigated cell lines in vitro in a cell autonomous manner, which represents a non-physiological situation. Conclusions based on such work might not necessarily be transferrable to disease states in which synchronized, non-cell autonomous effects occur. Here, we summarize the current knowledge of the pathophysiological relevance of necroptosis in vivo, and in light of this understanding, we reassess the morphological classification of necrosis that is generally used by pathologists. Along these lines, we discuss the paucity of data implicating necroptosis in human disease. Finally, the in vivo relevance of non-necroptotic forms of necrosis, such as ferroptosis, is addressed.

A Mini-Review on the Effect of Docosahexaenoic Acid (DHA) on Cerulein-Induced and Hypertriglyceridemic Acute Pancreatitis

Acute pancreatitis refers to the sudden inflammation of the pancreas. It is associated with premature activation and release of digestive enzymes into the pancreatic interstitium and systemic circulation, resulting in pancreatic tissue autodigestion and multiple organ dysfunction, as well as with increased cytokine production, ultimately leading to deleterious local and systemic effects. Although mechanisms involved in pathogenesis of acute pancreatitis have not been completely elucidated, oxidative stress is regarded as a major risk factor. In human acute pancreatitis, lipid peroxide levels in pancreatic tissues increase. Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid (C22:6n-3), exerts anti-inflammatory and antioxidant effects on various cells. Previous studies have shown that DHA activates peroxisome proliferator-activated receptor-γ and induces catalase, which inhibits oxidative stress-mediated inflammatory signaling required for cytokine expression in experimental acute pancreatitis using cerulein. Cerulein, a cholecystokinin analog, induces intra-acinar activation of trypsinogen in the pancreas, which results in human acute pancreatitis-like symptoms. Therefore, DHA supplementation may be beneficial for preventing or inhibiting acute pancreatitis development. Since DHA reduces serum triglyceride levels, addition of DHA to lipid-lowering drugs like statins has been investigated to reduce hypertriglyceridemic acute pancreatitis. However, high DHA concentrations increase cytosolic Ca²⁺, which activates protein kinase C and may induce hyperlipidemic acute pancreatitis. In this review, effect of DHA on cerulein-induced and hypertriglyceridemic acute pancreatitis has been discussed. The relation of high concentration of DHA to hyperlipidemic acute pancreatitis has been included.

The effect of Chinese herbal medicine on non-biliogenic severe acute pancreatitis: a systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

More and more clinicians and researchers have realized that clinical trials are necessary to define clinical efficacy effect. Even though the number has been substantially growing for the past years, the finished and reported trials are limited. Nevertheless, those documented trials are important and precious, and comprehensive evaluation and analysis of them are warranted at current stage. Our goal was to evaluate the effect of Chinese herbal medicine (CHM) on non-biliogenic severe acute pancreatitis (SAP) by conducting a systematic review and meta-analysis of prospective randomized controlled studies.

METHODS

Relevant studies were identified by PubMed, Cochrane Library, EMBASE, China Biomedical Database web (CBM), China National Knowledge Infrastructure Databases (CNKI), and Wanfang database up to 2014.Reference lists of retrieved articles were also reviewed. Two reviewers independently assessed studies for inclusion and extracted data. The main outcome data of trials were analyzed by using RevMan5.2. Odds ratio (OR) or mean difference (MD) with a 95% confidence interval (CI) was used as effect measure. Either a fixed or a random-effect model was used to evaluate the effect of CHM on non-biliogenic SAP.

RESULTS

Twenty two prospective randomized controlled studies involving 1388 participants were included in the meta-analysis. CHM was tested to be more effective than reference group: Mortality [OR: 0.43, 95% CI (0.29, 0.64)], overall efficiency [OR: 4.0, 95% CI (2.72, 5.89)], operability [OR: 0.313, 95% CI (0.21, 0.46)], rate of complications [OR: 0.37, 95% CI (0.27, 0.50)], Length of hospitalization [MD: -9.70, 95% CI (-12.88, -6.51)] compared with reference group.

CONCLUSIONS

No serious adverse events were reported. This meta-analysis provides evidence suggesting that CHM seems to be an effective and safe treatment for people with non-biliogenic severe acute pancreatitis (SAP). However, the poor methodological quality of most of the trials means that we may be unable to reach a definitive conclusion. Hence, the effect of CHM in the treatment of non-biliogenic SAP warrants rigorously designed, multicentre, large-scale trials with higher quality worldwide.

Dendritic cells promote pancreatic viability in mice with acute pancreatitis

BACKGROUND & AIMS

The cellular mediators of acute pancreatitis are incompletely understood. Dendritic cells (DCs) can promote or suppress inflammation, depending on their subtype and context. We investigated the roles of DC in development of acute pancreatitis.

METHODS

Acute pancreatitis was induced in CD11c.DTR mice using caerulein or L-arginine; DCs were depleted by administration of diphtheria toxin. Survival was analyzed using Kaplan-Meier method.

RESULTS

Numbers of major histocompatibility complex II(+)CD11c(+) DCs increased 100-fold in pancreata of mice with acute pancreatitis to account for nearly 15% of intrapancreatic leukocytes. Intrapancreatic DCs acquired a distinct immune phenotype in mice with acute pancreatitis; they expressed higher levels of major histocompatibility complex II and CD86 and increased production of interleukin-6, membrane cofactor protein-1, and tumor necrosis factor-α. However, rather than inducing an organ-destructive inflammatory process, DCs were required for pancreatic viability; the exocrine pancreas died in mice that were depleted of DCs and challenged with caerulein or L-arginine. All mice with pancreatitis that were depleted of DCs died from acinar cell death within 4 days. Depletion of DCs from mice with pancreatitis resulted in neutrophil infiltration and increased levels of systemic markers of inflammation. However, the organ necrosis associated with depletion of DCs did not require infiltrating neutrophils, activation of nuclear factor-κB, or signaling by mitogen-activated protein kinase or tumor necrosis factor-α.

CONCLUSIONS

DCs are required for pancreatic viability in mice with acute pancreatitis and might protect organs against cell stress.

Inhibitory mechanism of lycopene on cytokine expression in experimental pancreatitis

Reactive oxygen species (ROS) are important mediators to induce pancreatitis. Serum levels of antioxidant enzymes and carotenoids including lycopene are lower in patients with pancreatitis than those of healthy subjects. The cholecystokinin (CCK) analog cerulein induces similar pathologic events as shown in human pancreatitis. Recent studies show that high doses of cerulein activate NF-κB and induce the expression of inflammatory cytokines, in pancreatic acinar cells, which is mediated by the activation of NADPH oxidase. Lycopene functions as a very potent antioxidant to suppress the induction of inflammatory cytokines, in pancreatic acinar cells stimulated with cerulein. In this review, the possible beneficial effect of lycopene on experimental pancreatitis shall be discussed based on its antioxidant activity.

Anti-inflammatory effects of peritoneal lavage in acute pancreatitis

OBJECTIVES

Intraperitoneal administration of trypsin stimulates the production of cytokines from peritoneal macrophages. Removing the pancreatitis-associated ascitic fluid from the peritoneal cavity may decrease the systemic inflammatory response in acute pancreatitis (AP). We investigated the effect of peritoneal lavage on the systemic inflammatory response in severe AP.

METHODS

Acute pancreatitis was induced in Wistar rats by 5% taurocholate intraductal injection. Peritoneal lavage was performed for 4 hours after onset of AP. At 4 hours after induction of AP, serum samples were assayed for amylase and inflammatory cytokines (tumor necrosis factor α, interleukin-6 [IL-6], and IL-10). Expression of pancreatic cyclooxygenase-2 and inducible nitric oxide synthase, liver mitochondrial function, and pulmonary myeloperoxidase activities were determined.

RESULTS

Peritoneal lavage after AP led to a decrease in serum levels of tumor necrosis factor α and IL-6 and an increase in IL-10. In the pancreas, this treatment reduced cyclooxygenase-2 and inducible nitric oxide synthase expression. Liver mitochondrial dysfunction was also reduced. There were no differences on serum amylase levels and pulmonary myeloperoxidase between groups with AP.

CONCLUSIONS

Peritoneal lavage has a systemic anti-inflammatory effect in severe AP and may be able to decrease the severity of severe AP.

CO2 abdominal insufflation decreases local and systemic inflammatory response in experimental acute pancreatitis

OBJECTIVES

Acute pancreatitis (AP) is a serious disease that is amplified by an associated systemic inflammatory response. We investigated the effect of CO2 pneumoperitoneum on the local and systemic inflammatory response in AP.

METHODS

Acute pancreatitis was induced in Wistar rats by 5% taurocholate intraductal injection. Carbon dioxide pneumoperitoneum was applied for 30 minutes before the induction of AP. Inflammatory parameters were evaluated in the peritoneum (ascites, cell number, and tumor necrosis factor alpha [TNF-alpha]), serum (amylase, TNF-alpha, interleukin-6 [IL-6], and IL-10), pancreas (myeloperoxidase [MPO] activity, cyclo-oxygenase 2 and inducible nitric oxide synthase expression, and histological diagnosis), liver, and lung (mitochondria dysfunction and MPO activity).

RESULTS

Abdominal insufflation with CO2 before induction of AP caused a significant decrease in ascites volume, cells, and TNF-alpha in the peritoneal cavity and in serum TNF-alpha and IL-6 but not IL-10 levels. In the pancreas, this treatment reduced MPO activity, acinar and fat necrosis, and the expression of inducible nitric oxide synthase and cyclo-oxygenase 2. There were no significant differences on serum amylase levels, liver mitochondrial function, and pulmonary MPO between groups.

CONCLUSIONS

Our data demonstrated that CO2 pneumoperitoneum reduced pancreatic inflammation and attenuated systemic inflammatory response in AP. This article suggests that CO2 pneumoperitoneum plays a critical role on the better outcome in patients undergoing laparoscopic pancreatic surgery.

Cerulein pancreatitis: oxidative stress, inflammation, and apoptosis

Cerulein pancreatitis is similar to human edematous pancreatitis, manifesting with dysregulation of digestive enzyme production and cytoplasmic vacuolization, the death of acinar cells, edema formation, and infiltration of inflammatory cells into the pancreas. Reactive oxygen species are involved in nuclear factor-kappaB activation, cytokine expression, apoptosis and pathogenesis of pancreatitis. There is recent evidence that cerulein activates NADPH oxidase, which is a major source of reactive oxygen species during inflammation and apoptosis in pancreatic acinar cells. In addition, the Janus kinase/signal transducer and activator of transcription pathway has been suggested as being involved in inflammatory signaling in the pancreas. This review discusses the involvement of oxidative stress in inflammation and apoptosis in pancreatic acinar cells stimulated with cerulein as an in vitro model of pancreatitis.

The effect of emodin-assisted early enteral nutrition on severe acute pancreatitis and secondary hepatic injury

Severe acute pancreatitis (SAP) characterized by atrocious progression and numerous complications often leads to a high mortality rate due to hypermetabolism, systemic inflammatory response syndrome (SIRS), and multiple organs dysfunction syndrome (MODS). Studies have revealed that both early enteral nutrition (EEN) and emodin are potent agents in the management of SAP. However, whether the combined strategy is rational and more effective than either one alone remains unknown. In this regard, Wistar rats were treated with emodin-assisted EEN (EAEEN) through enteral nutrient tubes after induction of SAP by retrograde infusion of 5.0% sodium taurocholate into the common pancreatic duct. Serum levels of amylase, tumor necrosis factor-alpha (TNF-α), angiotensin II (AngII), maleic dialdehyde (MDA), glutamic pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST) and C-reactive protein (CRP), intestinal secretory IgA (SIgA), pancreatic and hepatic myeloperoxidase (MPO) activity as well as plasma levels of D-lactate and endotoxin were measured. In addition, pathologic alterations of pancreas and liver were observed microscopically. We found that EAEEN could significantly ameliorate these parameters and prevent pancreas and liver from serious damage. In conclusion, Our results indicated that EAEEN could exert beneficial effects on experimental SAP and obviously abate the severity of secondary hepatic injury. The combined strategy was safe and more effective than either one alone in the acute stage of SAP. This study also provided an experimental base for the clinical treatment of SAP patients with EAEEN.

5-lipoxygenase knockout mice exhibit a resistance to acute pancreatitis induced by cerulein

Here we compare the degree of pancreatitis caused by cerulein in mice lacking 5-lipoxygenase (5-LO) and in the corresponding wild-type mice. Intraperitoneal injection of cerulein in mice resulted in severe, acute pancreatitis characterized by oedema, neutrophil infiltration and necrosis and elevated serum levels of amylase and lipase. Infiltration of pancreatic and lung tissue with neutrophils (measured as increase in myeloperoxidase activity) was associated with enhanced lipid peroxidation (increased tissue levels of malondialdehyde). Immunohistochemical examination demonstrated a marked increase in immunoreactivity for intracellular adhesion molecule-1 (ICAM-1), P-selectin and E-selectin in the pancreas and lung of cerulein-treated mice. In contrast, the degree of (1) pancreatic inflammation and tissue injury (histological score), (2) up-regulation/expression of P-selectin, E-selectin and ICAM-1, and (3) neutrophil infiltration was markedly reduced in pancreatic and lung tissue obtained from cerulein-treated 5-LO-deficient mice. These findings support the view that 5-LO plays an important, pro-inflammatory role in the acute pancreatitis caused by cerulein in mice.

Intra-alveolar urinary trypsin inhibitor cannot inhibit polymorphonuclear elastase activity in the lung in postsurgical patients with acute respiratory distress syndrome

The aim of this study was to evaluate the concentrative relationship between polymorphonuclear elastase (PMNE) and urinary trypsin inhibitor (UTI) in the bronchoalveolar lavage fluid (BALF) of patients with acute respiratory distress syndrome (ARDS). A total of eight patients who developed ARDS after gastroenterological surgery and eight patients with normal respiratory function during general anesthesia using tracheal intubation were the subjects of this study. BALF was collected from the right middle lobe using saline, and the PMNE and UTI concentrations were measured. The PMNE concentrations were 1277 +/- 1589 ng/ml and 38 +/- 26 ng/ml in the patients with ARDS and those with normal lung function, respectively, and the UTI concentrations were 225 +/- 175 mU/ml and 81 +/- 40 mU/ml, respectively, expressed as mean +/- SD. Based on the UTI concentration which can inhibit PMNE activity, the PMNE concentration in the ARDS patients was not entirely inhibited by UTI. Since only UTI can inhibit PMNE activity in the inflammatory tissues, PMNE in the BALF may induce and aggravate lung injury in ARDS. Thus, we conclude that PMNE released from activated neutrophils in the lung is associated with the development of ARDS.

Blood concentrations of polymorphonuclear leucocyte elastase and interleukin-6 are indicators for the occurrence of multiple organ failures at the early stage of acute pancreatitis

We studied potential indicators of severe acute pancreatitis by measuring the blood concentrations of various cytokines, polymorphonuclear leucocyte elastase (PMN-E), acute phase reactants, pancreatic amylase (P-AMY), pancreatic elastase-1 (E-1) and white blood cell (WBC) counts in patients with acute pancreatitis. In addition, the presence of multiple organ damage was assessed. Subjects consisted of 22 patients with acute pancreatitis including severe (n = 11), moderate (n = 4) and mild (n = 7) cases. A significant positive correlation was observed between the number of organs damaged and the peak concentrations of interleukin (IL)-6, PMN-E, C-reactive protein (CRP) and pancreatic secretory trypsin inhibitor (PSTI). Among these markers, blood concentrations of PMN-E and IL-6 rapidly increased and peaked at the early phase of acute pancreatitis whereas CRP and PSTI did not. The elevation of PMN-E and IL-6 was greater the more severe the symptoms. However, no significant correlation was observed between the number of organs damaged and the maximum serum concentrations of P-AMY and E-1, or the WBC count, which have been considered to be markers of pancreatitis. These results suggest that PMN-E and IL-6 concentrations are useful indicators of severity and prognosis and their determination facilitates the selection of appropriate treatment in the early stages of disease to prevent the aggressive progression of acute pancreatitis.

Poor prognosis in esophageal cancer patients with postoperative complications

We investigated the relationship between postoperative complications and prognosis in esophageal cancer patients. Two hundred five patients with esophageal cancer were divided into three case groups. Group A (n = 100) consisted of cases without postoperative complications. Groups B (n = 58) and C (n = 47) consisted of cases with minor and major postoperative complications. The 5-year survival rates were 41.8%, 21.3%, and 20.2% in groups A, B, and C, respectively. There was a significant difference in the prognosis between groups A and B, and also between groups A and C. Any patients who died within 5 years without a relapse their cases were excluded from the study; the 5-year survival rates were 46.7%, 32.3%, and 22.5% in groups A, B, and C, respectively, with a significant difference between groups A and B. There were no significant differences between the three groups regarding the patient characteristics. These results therefore indicate that postoperative complications might contribute to a poor prognosis in cancer patients.

The protective effects of long-acting recombinant human pancreatic secretory trypsin inhibitor (R44S-PSTI) in a rat model of cerulein-induced pancreatitis

The effects of pancreatic secretory trypsin inhibitor (PSTI) on cerulein-induced pancreatitis were studied in a rat model. Arg44 of PSTI was replaced by Ser using site-directed mutagenesis (R44S-PSTI). R44S-PSTI has a longer half-life than the natural form. Pancreatitis was induced by four intramuscular injections of cerulein (50 microgram/kg at 1 h intervals). Continuous intravenous infusion of R44S-PSTI began at a dose of 20 micrograms/kg/h 30 min before the first cerulein injection, and was completed 3 h after the last cerulein injection. Tumour necrosis factor (TNF-alpha) production by isolated peritoneal macrophages from rats with cerulein-induced pancreatitis increased following lipopolysaccharide stimulation, compared to control rats (P < 0.01). R44S-PSTI administration significantly decreased the TNF-alpha production by peritoneal macrophages from rats with cerulein-induced pancreatitis (P < 0.05). In addition, R44S-PSTI significantly reduced serum amylase activity (P < 0.01) and pancreatic wet weight after pancreatitis induction (P < 0.05). Histological examination revealed marked acinar cell vacuolization, interstitial oedema, and cellular infiltration in cerulein-induced pancreatitis, but a lesser degree of histological change in rats that were treated with R44S-PSTI. Prophylactic use of intravenous R44S-PSTI infusion may reduce the severity of acute pancreatitis either histologically or serologically.

Interleukins in acute pancreatitis

Cytokines and their endogenous antagonists are released from inflammatory cells during acute pancreatitis, in particular its severe form. They can be found early in the course of the disease as is shown in animal models and in endoscopic retrograde cholangio-pancreatography (ERCP) induced human pancreatitis. Cytokine measurements can predict the course of the disease. This can, however, be achieved using more simple parameters, such as clinical judgement and leucocyte elastase. Anticytokine strategies in the treatment of severe acute pancreatitis should be further evaluated since some positive effects have been found in experimental settings. Interleukin 10 or soluble TNF alpha-receptors may be good candidates. Plasmapheresis seems to change cytokine-anticytokines patterns and this also needs to be explored in controlled trials.