Tumor necrosis factor α antibody prevents brain damage of rats with acute necrotizing pancreatitis

Experimental Acute Pancreatitis Models: History, Current Status, and Role in Translational Research

Acute pancreatitis is a potentially severe inflammatory disease that may be associated with a substantial morbidity and mortality. Currently there is no specific treatment for the disease, which indicates an ongoing demand for research into its pathogenesis and development of new therapeutic strategies. Due to the unpredictable course of acute pancreatitis and relatively concealed anatomical site in the retro-peritoneum, research on the human pancreas remains challenging. As a result, for over the last 100 years studies on the pathogenesis of this disease have heavily relied on animal models. This review aims to summarize different animal models of acute pancreatitis from the past to present and discuss their main characteristics and applications. It identifies key studies that have enhanced our current understanding of the pathogenesis of acute pancreatitis and highlights the instrumental role of animal models in translational research for developing novel therapies.

Effects of dexmedetomidine on anesthesia recovery period and postoperative cognitive function of patients after robot-assisted laparoscopic radical cystectomy

OBJECTIVE

The purpose of the study was to evaluate the neuroprotective effect of dexmedetomidine on anesthesia recovery period and postoperative cognitive function of patients after robot-assisted laparoscopic radical cystectomy and ileal conduit diversion.

METHODS

A total of 40 elective patients who would undergo robot-assisted laparoscopic radical cystectomy and ileal conduit diversion. They were randomly divided into two groups in a double-blind manner. After pneumoperitoneum established, all patients adopted 40° trendelenberg position. Mean arterial pressure (MAP), heart rate (HR), and bispectral index (BIS) of each patient were recorded at four moments respectively, namely the end of surgery (T0), palinesthesia (T1), extubation (T2), 10 min after extubation (T3).

RESULTS

In the dexmedetomidine group, the mean arterial pressure and heart rate decreased at T1 and T2 compared with controls (P<0.05); in addition, the delirium rating scale was lower than the latter (P<0.05) while Ramsay sedation score was significantly higher (P<0.05). POCD was observed on 28 patients, containing 17 controls and 11 dexmedetomidine individuals, one day after operation, and 21 patients (12 controls, 9 dexmedetomidine people) five days after operation. One- and five-day after operation, the levels of TNF-α, NSE and IL-6 in the dexmedetomidine group were significantly lower than those in the control group (P<0.05), and serum SOD significantly increased in the former (P<0.05).

CONCLUSION

Dexmedetomidine had a neuroprotective effect on anesthesia recovery and postoperative period of the elderly patients undergone robot-assisted laparoscopic radical cystectomy, which might be related to the reduction of inflammatory reaction induced by dexmedetomidine.

Angelicin regulates LPS-induced inflammation via inhibiting MAPK/NF-κB pathways

BACKGROUND

Angelicin is a furocoumarin found in Psoralea corylifolia L. fruit. The purpose of this study was to investigate the protective ability of angelicin against inflammation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and LPS-induced in vivo acute lung injury model.

MATERIALS AND METHODS

The concentrations of tumor necrosis factor alpha (TNF-α) and interleukin (IL)-6 in the culture supernatants of RAW 264.7 cells were determined 24 h after LPS administration. ALI was induced by intratracheal instillation of LPS. Six hours after LPS inhalation, bronchoalveolar lavage fluid and lung tissue samples were obtained for enzyme-linked immunosorbent assay, histologic, and Western blotting analyses.

RESULTS

The results showed that pretreatment with angelicin markedly downregulated TNF-α and IL-6 levels in vitro and in vivo, and significantly decreased the amount of inflammatory cells, lung wet-to-dry weight ratio, and myeloperoxidase activity in LPS-induced ALI mice. Furthermore, Western blotting analysis results demonstrated that angelicin blocked the phosphorylation of IκBα, NF-κBp65, p38 MAPK, and JNK in LPS-induced ALI.

CONCLUSIONS

These results suggest that angelicin was potentially advantageous to prevent inflammatory diseases by inhibiting NF-κB and MAPK pathways. Our data indicated that angelicin might be a potential new agent for prevention of inflammatory reactions and diseases in the clinic.

Experimental pancreatitis results in increased blood-brain barrier permeability in rats: a potential role of MCP-1

OBJECTIVE

To measure the changes of blood-brain barrier (BBB) permeability in rats with acute pancreatitis (AP) and to investigate the role of monocyte chemoattractant protein (MCP)-1 expression in this alteration.

METHODS

Rat model of severe acute pancreatitis (SAP) and mild acute pancreatitis (MAP) was induced by pancreatic duct infusion of 5% and 0.5% sodium choleate, respectively, and a saline infusion was used in the control. The severity of AP was evaluated by a pathological score system. BBB permeability was detected by Evan's blue tracer and BBB tight junction was assessed by brain occludin expression. Immunohistochemistry and real-time polymerase chain reaction were used to detect MCP-1 expression in the brain. Nifedipine was used as the antagonist of MCP-1.

RESULTS

Compared to the control group, change of BBB permeability was more significant in SAP groups, but not in MAP groups. Occludin level decreased 12 h after SAP induction. Pathological score of SAP group was higher than that in MAP group. BBB opening was associated with pancreatic injury. Brain MCP-1 expression was detected in all the SAP groups, which was correlated with increased BBB permeability, but was not found in the control group or the MAP group. After treatment with nifedipine, brain MCP-1 level decreased and BBB function improved synchronously in SAP groups.

CONCLUSIONS

BBB permeability increased in SAP significantly and time-dependently, and was correlated with brain MCP-1 expression. Nifedipine may improve BBB function by inhibiting MCP-1 expression.

Review of experimental animal models of biliary acute pancreatitis and recent advances in basic research

Acute pancreatitis (AP) is a formidable disease, which, in severe forms, causes significant mortality. Biliary AP, or gallstone obstruction-associated AP, accounts for 30-50% of all clinical cases of AP. In biliary AP, pancreatic acinar cell (PAC) death (the initiating event in the disease) is believed to occur as acinar cells make contact with bile salts when bile refluxes into the pancreatic duct. Recent advances have unveiled an important receptor responsible for the major function of bile acids on acinar cells, namely, the cell surface G-protein-coupled bile acid receptor-1 (Gpbar1), located in the apical pole of the PAC. High concentrations of bile acids induce cytosolic Ca(2+) overload and inhibit mitochondrial adenosine triphosphate (ATP) production, resulting in cell injury to both PACs and pancreatic ductal epithelial cells. Various bile salts are employed to induce experimental AP, most commonly sodium taurocholate. Recent characterization of taurolithocholic acid 3-sulphate on PACs has led researchers to focus on this bile salt because of its potency in causing acinar cell injury at relatively low, sub-detergent concentrations, which strongly implicates action via the receptor Gpbar1. Improved surgical techniques have enabled the infusion of bile salts into the pancreatic duct to induce experimental biliary AP in mice, which allows the use of these transgenic animals as powerful tools. This review summarizes recent findings using transgenic mice in experimental biliary AP.

Protective effects and mechanisms of Baicalin and octreotide on renal injury of rats with severe acute pancreatitis

AIM

To investigate the protective effects and mechanisms of Baicalin and octreotide on renal injury of rats with severe acute pancreatitis (SAP).

METHODS

One hundred and eighty SD rats were randomly assigned to the model group, Baicalin-treated group, octreotide-treated group and sham operation group. The mortality, plasma endotoxin level, contents of blood urea nitrogen (BUN), creatinine (CREA), phospholipase A2 (PLA2), nitrogen monoxide (NO), tumor necrosis factor (TNF)-alpha, IL-6 and endothelin-1 (ET-1) in serum, expression levels of renal Bax and Bcl-2 protein, apoptotic indexes and pathological changes of kidney were observed at 3, 6 and 12 h after operation.

RESULTS

The renal pathological changes were milder in treated group than in model group. The survival at 12 h and renal apoptotic indexes at 6 h were significantly (P<0.05) higher in treated group than in model group [66.67% vs 100%; 0.00 (0.02)% and 0.00 (0.04)% vs 0.00 (0.00)%, respectively]. The serum CREA content was markedly lower in octreotide-treated group than in model group at 3 h and 6 h (P<0.01, 29.200+/-5.710 micromol/L vs 38.400+/-11.344 micromol/L; P<0.05, 33.533+/-10.106 micromol/L vs 45.154+/-17.435 micromol/L, respectively). The expression level of renal Bax protein was not significantly different between model group and treated groups at all time points. The expression level of renal Bcl-2 protein was lower in Baicalin-treated group than in model group at 6 h [P<0.001, 0.00 (0.00) grade score vs 3.00 (3.00) grade score]. The Bcl-2 expression level was lower in octreotide-treated group than in model group at 6 h and 12 h [P<0.05, 0.00 (0.00) grade score vs 3.00 (3.00) grade score; 0.00 (0.00) grade score vs 0.00 (1.25) grade score, respectively]. The serum NO contents were lower in treated groups than in model group at 3 h and 12 h [P<0.05, 57.50 (22.50) and 52.50 (15.00) micromol/L vs 65.00 (7.50) micromol/L; P<0.01, 57.50 (27.50) and 45.00 (12.50) micromol/L vs 74.10 (26.15) micromol/L, respectively]. The plasma endotoxin content and serum BUN content (at 6 h and 12 h) were lower in treated groups than in model group. The contents of IL-6, ET-1, TNF-alpha (at 6 h) and PLA2 (at 6 h and 12 h) were lower in treated groups than in model group [P<0.001, 3.031 (0.870) and 2.646 (1.373) pg/mL vs 5.437 (1.025) pg/mL; 2.882 (1.392) and 3.076 (1.205) pg/mL vs 6.817 (0.810) pg/mL; 2.832 (0.597) and 2.462 (1.353) pg/mL vs 5.356 (0.747) pg/mL; 16.226 (3.174) and 14.855 (5.747) pg/mL vs 25.625 (7.973) pg/mL; 18.625 (5.780) and 15.185 (1.761) pg/mL vs 24.725 (3.759) pg/mL; 65.10 (27.51) and 47.60 (16.50) pg/mL vs 92.15 (23.12) pg/mL; 67.91+/-20.61 and 66.86+/-22.10 U/mL, 63.13+/-26.31 and 53.63+/-12.28 U/mL vs 101.46+/-14.67 and 105.33+/-18.10 U/mL, respectively].

CONCLUSION

Both Baicalin and octreotide can protect the kidney of rats with severe acute pancreatitis. The therapeutic mechanisms of Baicalin and octreotide might be related to their inhibition of inflammatory mediators and induction of apoptosis. Baicalin might be a promising therapeutic tool for severe acute pancreatitis.

Pathogenesis of hepatic encephalopathy: the tumour necrosis factor-alpha theory

Hepatic encephalopathy (HE) is a major complication for acute and chronic liver failure. Despite several decades of intensive clinical and basic research, the pathogenesis of HE is still incompletely understood, and the precise mechanisms causing brain dysfunction in liver failure are still not fully established. Several theories concerning the pathogenesis of HE have been previously suggested, including the ammonia theory, which received the most attention. These theories are not mutually exclusive and the validity of none of them has been definitely proved experimentally. In this review article, an attractive theory concerning the pathogenesis of HE, the tumour necrosis factor-alpha (TNF) theory, is presented and comprehensively discussed after accumulation of sufficient data which indicate that the pro-inflammatory cytokine, TNF, is strongly involved in the pathogenesis of HE associated with both acute and chronic liver failure. This theory seems to be superior to all other previous theories in the pathogenesis of HE, and may induce development of other beneficial therapeutical modalities for HE directed towards inhibition of TNF production and/or action, and towards enhancement of its degradation.

Acute pancreatitis: animal models and recent advances in basic research

Acute pancreatitis (AP) is characterized by edema, acinar cell necrosis, hemorrhage, and severe inflammation of the pancreas. Patients with AP present with elevated blood and urine levels of pancreatic digestive enzymes, such as amylase and lipase. Severe AP may lead to systemic inflammatory response syndrome and multiorgan dysfunction syndrome, which account for the high mortality rate of AP. Although most (>80%) cases of AP are associated with gallstones and alcoholism, some are idiopathic. Although the pathogenesis of AP has not yet been elucidated, a common feature is the premature activation of trypsinogen within pancreatic tissues, which triggers autodigestion of the gland. Recent advances in basic research suggest that etiologic factors including cyclooxygenase-2, substance P, and angiotensin II may have novel roles in this disease. Basic research data obtained thus far have been based on animal models of AP ranging from mild edematous pancreatitis to severe necrotizing pancreatitis. In view of this, an adequate selection of experimental animal models is of paramount importance. Notwithstanding these animal models, it should be emphasized that none of these models mimic the clinical situation where varying degrees of severity usually occur. In this review, commonly used animal models of AP will be critically evaluated. A discussion of recent advances in our knowledge about AP risk factors is also included.

The molecular basis of paediatric malarial disease

Severe falciparum malaria is an acute systemic disease that can affect multiple organs, including those in which few parasites are found. The acute disease bears many similarities both clinically and, potentially, mechanistically, to the systemic diseases caused by bacteria, rickettsia, and viruses. Traditionally the morbidity and mortality associated with severe malarial disease has been explained in terms of mechanical obstruction to vascular flow by adherence to endothelium (termed sequestration) of erythrocytes containing mature-stage parasites. However, over the past few decades an alternative ‘cytokine theory of disease’ has also evolved, where malarial pathology is explained in terms of a balance between the pro- and anti-inflammatory cytokines. The final common pathway for this pro-inflammatory imbalance is believed to be a limitation in the supply and mitochondrial utilisation of energy to cells. Different patterns of ensuing energy depletion (both temporal and spatial) throughout the cells in the body present as different clinical syndromes. This chapter draws attention to the over-arching position that inflammatory cytokines are beginning to occupy in the pathogenesis of acute malaria and other acute infections. The influence of inflammatory cytokines on cellular function offers a molecular framework to explain the multiple clinical syndromes that are observed during acute malarial illness, and provides a fresh avenue of investigation for adjunct therapies to ameliorate the malarial disease process.

Human malarial disease: a consequence of inflammatory cytokine release

Malaria causes an acute systemic human disease that bears many similarities, both clinically and mechanistically, to those caused by bacteria, rickettsia, and viruses. Over the past few decades, a literature has emerged that argues for most of the pathology seen in all of these infectious diseases being explained by activation of the inflammatory system, with the balance between the pro and anti-inflammatory cytokines being tipped towards the onset of systemic inflammation. Although not often expressed in energy terms, there is, when reduced to biochemical essentials, wide agreement that infection with falciparum malaria is often fatal because mitochondria are unable to generate enough ATP to maintain normal cellular function. Most, however, would contend that this largely occurs because sequestered parasitized red cells prevent sufficient oxygen getting to where it is needed. This review considers the evidence that an equally or more important way ATP deficiency arises in malaria, as well as these other infectious diseases, is an inability of mitochondria, through the effects of inflammatory cytokines on their function, to utilise available oxygen. This activity of these cytokines, plus their capacity to control the pathways through which oxygen supply to mitochondria are restricted (particularly through directing sequestration and driving anaemia), combine to make falciparum malaria primarily an inflammatory cytokine-driven disease.

Changes of endotoximia, cytokines and nitric oxide and therapeutic effects of sandostatin in rats with severe acute pancreatitis

AIM: To study the roles of endotoximia, cytokines and nitric oxide in the development of severe acute pancreatitis (SAP) and the therapeutic effects of sandostatin (SS) in rats.

METHODS: SAP models were induced by retrograde injection of 15 g/L sodium deoxycholate and then treated by SS. The plasma levels of endotoxin (ET), lipid peroxide (LPO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and nitric oxide (NO), as well as the expression LPO, TNF-α, IL-6 and NO in pancreatic tissues, were measured. The changes of pancreatic histology were examined under light microscope.

RESULTS: As Compared with those in sham operation group, the plasma levels of ET, LPO, TNF-α, IL-6 and NO were markedly higher in SAP group (P < 0.01), and the changes of ET, LPO, TNF-α and NO at 6 h were higher (898 ± 114 EU/L, 24.58 ± 1.23 μmol/L, 246.3 ± 16.5 ng/L, 162.8 ± 10.9 mmol/L, P < 0.05) than those at 12 and 24 h. The changes of LPO, TNF-α, IL-6 and NO in pancreatic tissues of SAP group were obviously higher in comparison with those of sham group (3.31 ± 0.85 μmol/g vs0.33 ± 0.04 μmol/g, P < 0.01; 2.57 ± 0.14 ng/g vs 0.16 ± 0.04 ng/g, P < 0.01; 85.6 ± 24.6 ng/g vs 32.5 ± 5.7 ng/g, P < 0.01; 15.3 ± 1.2 mmol/g vs 6.6 ± 1.4 mmol/g, P < 0.01); and severe damages of pancreatic tissues were observed under light microscope. In SAP group, the plasma levels of LPO, TNF-α, IL-6 and NO were significantly correlated with ET level (r = 0.858,P < 0.01; r = 0.958, P < 0.01; r = 0.918, P < 0.01; r = 0.875, P < 0.01). The indexes mentioned above in SS group were obviously ameliorated in comparison with those in SAP group (P < 0.01).

CONCLUSION: Endotoximia, cytokines and NO play important roles in the development of severe acute pancreatitis. Sandostatin can block the chain reaction caused by these factors.

N/A

N/A