Prior peritoneal lavage with hot 0.9 % saline induces HSP70 expression and protects against cerulein-induced acute pancreatitis in rats

Recent studies have indicated that pre-induction of heat shock protein 70 (HSP70) expression in the pancreas protects against secretagogue-induced pancreatitis. In those studies, the HSP70 was mostly induced by unfeasible conditions. The aim of this current study was to investigate the effect of peritoneal lavage with hot 0.9 % saline (42 °C) on the pancreatic expression of HSP70 and its protective effect on cerulein-induced acute pancreatitis in rats. Male Wistar rats were peritoneally lavaged with 0.9 % saline at 42 °C for 30 min. HSP70 expression was evaluated by western blotting analysis. Prior peritoneal lavages with hot and warm saline were performed. Acute pancreatitis was induced by administration of intraperitoneal injection of cerulein (20 μg/kg) four times, and its severity was assessed by measuring serum amylase, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and trypsinogen activation peptide (TAP) levels. Pancreatic sections were stained with hematoxylin and eosin for histological evaluation. Peritoneal lavage with hot 0.9 % saline increased intrapancreatic HSP70 expression and ameliorated the cerulein-induced pancreatitis in rats, judged by the significantly reduced serum amylase, TNF-α, and IL-6 concentrations; histopathological scores, and serum TAP levels. Peritoneal lavage with hot 0.9 % saline can induce HSP70 expression and prevent cerulein-induced acute pancreatitis in rats. The results suggest that HSP70 protects against cerulein-induced pancreatitis by preventing proinflammatory cytokine synthesis and trypsinogen activation during acute pancreatitis.     

Adrenomedullin reduces the severity of cerulein-induced acute pancreatitis

We investigated the effect of Adrenomedullin (AM) on cerulein-induced acute pancreatitis in rats. AM treatment (100 ng/kg per rat, subcutaneous) after one hour of cerulein injection reduced the plasma amylase levels, pancreatic weight, pancreatic malondialdehyde (MDA) levels, and the severity of the lesions microscopically. These data suggest that AM has a protective effect on cerulein-induced acute pancreatitis. These could be due to anti-inflammatory properties of AM, inhibition of proinflammatory cytokine secretion, reducing the endothelial permeability increased by reactive oxygen species, endotoxins or cytokines.     

Interleukin-22 ameliorates cerulein-induced pancreatitis in mice by inhibiting the autophagic pathway

Pancreatitis occurs when digestive enzymes are activated in the pancreas. Severe pancreatitis has a 10-30% mortality rate. No specific treatments for pancreatitis exist now. Here, we discovered that interleukin-22 (IL-22) may have therapeutic potential in treating acute and chronic pancreatitis. Wild-type and IL-22 knockout mice were equally susceptible to cerulein-induced acute and chronic pancreatitis, whereas liver-specific IL-22 transgenic mice were completely resistant to cerulein-induced elevation of serum digestive enzymes, pancreatic necrosis and apoptosis, and inflammatory cell infiltration. Treatment of wild-type mice with recombinant IL-22 or adenovirus IL-22 markedly attenuated the severity of cerulein-induced acute and chronic pancreatitis. Mechanistically, we show that the protective effect of IL-22 on pancreatitis was mediated via the induction of Bcl-2 and Bcl-X(L), which bind to Beclin-1 and subsequently inhibit autophagosome formation to ameliorate pancreatitis. In conclusion, IL-22 ameliorates cerulein-induced pancreatitis by inhibiting the autophagic pathway. IL-22 could be a promising therapeutic drug to treat pancreatitis.     

Cinnamic acid nanoparticles modulate redox signal and inflammatory response in gamma irradiated rats suffering from acute pancreatitis

Acute Pancreatitis (AP) is a multifactorial disease. It was characterized by severe inflammation and acinar cell destruction. Thus, the present study was initiated to evaluate the role the of Cinnamic acid nanoparticles (CA-NPs) as a modulator for the redox signaling pathway involved in the development of pancreatitis. AP in rats was induced by L-arginine and exposure to gamma radiation. The pancreatic injury was evaluated using biochemical and histological parameters. Upon the oral administration of CA-NPs, both the severity of acute pancreatitis and the serum levels of amylase and lipase were decreased. Furthermore, the malondialdehyde (MDA) levels of the pancreatic tissue were significantly reduced and the depletion of glutathione was considerably restored. The injury and apoptosis of pancreatic tissues were markedly improved by the reduction of the caspase-3 levels. Additionally, the alleviation of pancreatic oxidative damage by CA-NPs was accompanied by a down-regulation of the NLRP3, NF-κB, and ASK1/MAPK signaling pathways. Collectively, the current findings showed that CA-NPs could protect the pancreatic acinar cell from injury not only by its antioxidant, anti-inflammatory effect but also by modulation of the redox-sensitive signal transduction pathways contributed to acute pancreatitis severity. Accordingly, cinnamic acid nanoparticles have therapeutic potential for the management of acute pancreatitis.     

The mtDNA nt7778 G/T Polymorphism Augments Formation of Lymphocytic Foci but Does Not Aggravate Cerulein-Induced Acute Pancreatitis in Mice

A polymorphism in the ATP synthase 8 (ATP8) gene of the murine mitochondrial genome, G-to-T transversion at position 7778, has been suggested to increase susceptibility to multiple autoimmune diseases, including autoimmune pancreatitis (AIP). The polymorphism also induces mitochondrial reactive oxygen species generation, secretory dysfunction and β-cell mass adaptation. Here, we have used two conplastic mouse strains, C57BL/6N-mtAKR/J (B6-mtAKR; nt7778 G; control) and C57BL/6N-mtFVB/N (B6-mtFVB; nt7778 T), to address the question if the polymorphism also affects the course of cerulein-induced acute pancreatitis in mice. Therefore, two age groups of mice (3 and 12-month-old, respectively) were subjected to up to 7 injections of the secretagogue cerulein (50 µg/kg body weight) at hourly intervals. Disease severity was assessed at time points from 3 hours to 7 days based on pancreatic histopathology, serum levels of α-amylase and activities of myeloperoxidase (MPO) in lung tissue. A comparison of cerulein-induced pancreatic tissue damage and increases of α-amylase and MPO activities showed no differences between the age-matched groups of both strains. Interestingly, histological evaluation of pancreatic tissue of both untreated and cerulein-treated B6-mtAKR and B6-mtFVB mice also revealed the presence of infiltrates of immune cells surrounding ducts and vessels; a finding that is compatible with an early stage of AIP. After recovery from cerulein-induced pancreatitis (day 7 after the injections), 12-month-old B6-mtFVB mice but not B6-mtAKR mice displayed aggravated lymphocytic lesions. A comparison of 12-month-old mice with other age groups of both strains revealed that lymphocytic foci were largely absent in 3-month-old mice, while 24-month-old mice were more affected. Together, our data suggest that the mtDNA nt7778 G/T polymorphism does not aggravate cerulein-induced acute pancreatitis. Autoimmune-like lesions, however, may progress faster if additional tissue damage occurs.     

Alpha-melanocyte stimulating hormone has beneficial effects on cerulein-induced acute pancreatitis

We investigated the effect of alpha-melanocyte stimulating hormone (alpha-MSH) on cerulein induced acute pancreatitis in rats. alpha-MSH treatment (50 microg per rat, intraperitoneally) prior to cerulein reduced the plasma amylase level, pancreatic weight, pancreatic myeloperoxidase activity and the severity of the lesions microscopically. These data suggest that alpha-MSH has a protective effect on cerulein-induced acute pancreatitis and this effect could be attributed, at least in part, to decreased tissue leukocyte infiltration and thus, to decreased pro-inflammatory cytokine production and/or oxygen- and nitrogen-derived reactive metabolite release.     

Prophylactic and therapeutic treatments with AT 1 and AT 2 receptor antagonists and their effects on changes in the severity of pancreatitis

Previous studies showed that a local pancreatic renin-angiotensin system (RAS) was upregulated in experimental acute pancreatitis. RAS inhibition could attenuate pancreatic inflammation and fibrosis, which casts a new light on the role of the pancreatic RAS in pancreatitis. The present study explores the prophylactic and therapeutic potentials, and possible molecular mechanism for the antagonism of angiotensin II receptors on the changes in the severity of pancreatic injury induced by acute pancreatitis. Experimental pancreatitis was induced by an intraperitoneal injection of supra-maximal dose of cerulein. The differential effects of angiotensin II receptors inhibitors losartan and PD123319 on the pancreatic injury were assessed by virtue of using the pancreatic water content, biochemical and histological analyses. Blockade of the AT(1) receptor by losartan at a dose of 200microg/kg could markedly ameliorate the pancreatic injury induced by cerulein, as evidenced by biochemical and histopathological studies. However, blockade of the AT(2) receptor by PD123319 appeared not to provide any beneficial role in cerulein-induced pancreatic injury. Both prophylactic and therapeutic treatments with losartan were effective against cerulein-induced pancreatic injury. The protective action of losartan was linked to an inhibition of NAD(P)H oxidase activity, thus consequential oxidative modification of pancreatic proteins in the pancreas. Inhibition of the AT(1) receptor, but not AT(2) receptor, may play a beneficial role in ameliorating the severity of acute pancreatitis. The differential effects of AT(1) and AT(2) inhibitors on cerulein-induced pancreatic injury might be due to the distinctive mechanism of the AT(1) and AT(2) receptors on the activation of NAD(P)H oxidase. Thus the protective role of AT(1) receptor antagonist, losartan, could be mediated by the inhibition of NAD(P)H oxidase-dependent generation of reactive oxygen species (ROS).     

Differential effects of saralasin and ramiprilat,the inhibitors of renin-angiotensin system,on cerulein-induced acute pancreatitis

Acute pancreatitis is an inflammatory disease characterized by pancreatic tissue edema, acinar cell necrosis, hemorrhage and inflammation of the damaged gland. It is believed that acinar cell injury is initiated by the activation of digestive zymogens inside the acinar cells, leading finally to the autodigestion of the pancreas. Previous study in our laboratory demonstrated that cerulein-induced acute pancreatitis was associated with an up-regulation of local renin-angiotensin system (RAS) in rat pancreas. Therefore, the utilization of RAS inhibitors may provide a novel and alternative treatment for acute pancreatitis. By means of a rat model of cerulein-induced acute pancreatitis, results from the present study showed that an intravenous injection of saralasin, an antagonist for angiotensin II receptors, at a dose of 40 microg/kg 30 min before the induction of acute pancreatitis significantly attenuated pancreatic edema. Results from the biochemical measurements showed that pretreatment with saralasin at a dose of 20 microg/kg markedly reduced pancreatic injury, as evidenced by the decreased activities of alpha-amylase and lipase in plasma. However, the same recipe of ramiprilat, a specific inhibitor for angiotensin-converting enzyme, at a dose of 20 microg/kg did not provide any protective effect against acute pancreatitis. On the contrary, pretreatment with ramiprilat at a dose 40 microg/kg enhanced cerulein-induced pancreatic injury. Results from histopathological analysis of these RAS inhibitors further confirmed with those results as obtained from biochemical analysis. These data indicate that administration of saralasin but not ramiprilat could be protective against acute pancreatitis and that activation of pancreatic RAS in acute pancreatitis may play a role in pancreatic tissue injury.     

Effect of hyperthermia on NF-kappaB binding activity in cerulein-induced acute pancreatitis

Although the pancreatic heat shock response has already been reported to confer protective effects during experimental pancreatitis, the mechanism of action remains unknown. We investigated the effects of hyperthermia in cerulein-induced pancreatitis. Heat shock protein 70 (HSP70) expression in rats was induced by a 20-min period of water immersion (42 degrees C). The severity of pancreatitis as well as the pancreatic expression of cytokines, nuclear factor-kappaB (NF-kappaB), and inhibitory factor kappaB-alpha (IkappaB-alpha) were evaluated in the presence and absence of hyperthermia. We found that hyperthermia resulted in time-dependent expression of HSP70 within the pancreas associated with a reduction in the severity of acute pancreatitis. Tumor necrosis factor-alpha and intercellular adhesion molecule-1 expression was significantly reduced in the presence of hyperthermia. Moreover, NF-kappaB activity was delayed in the presence of hyperthermia whereas IkappaB-alpha was stabilized in the cytoplasm. These results suggest that hyperthermia decreases the severity of cerulein-induced pancreatitis by decreasing cytokine expression in the pancreas through the modulation of NF-kappaB activity.     

Specific type IV phosphodiesterase inhibitor ameliorates cerulein-induced pancreatitis in rats

BACKGROUND AND AIMS: Type IV phosphodiesterase is a key enzyme to metabolize intracellular adenosine 3',5'-cyclic monophosphate (cAMP) expressed in inflammatory cells. The specific type IV phosphodiesterase inhibitor that increases intracellular cAMP is known to be potent suppressor of proinflammatory cytokines. However, the effect of phosphodiesterase inhibitors on the development of pancreatitis has not been well understood. In the present study, we examined the effect of a specific type IV phosphodiesterase inhibitor on experimentally induced pancreatitis. METHODS: Severity of cerulein-induced pancreatitis and pancreatic proinflammatory cytokine levels were studied with or without pretreatment with a specific type IV phosphodiesterase inhibitor (rolipram) in Sprague-Dawley rats. RESULTS: Administration of rolipram clearly ameliorated severity of pancreatitis evaluated by edema, serum amylase (P<0.05), and lipase levels (P<0.05) in rats. Also, the level of pancreatic proinflammatory cytokine (interleukin-1beta (IL-1beta)) was significantly reduced when rats were treated with rolipram prior cerulein injection (P<0.05). CONCLUSIONS: Our results demonstrated that intracellular cAMP and pancreatic proinflammatory cytokine level, which are regulated by type IV phosphodiesterase, might play an important role in the pathogenesis of acute pancreatitis.     

Reduction of inflammation and chronic tissue damage by omega-3 fatty acids in fat-1 transgenic mice with pancreatitis

Pancreatitis is a severe debilitating disease with high morbidity and mortality. Treatment is mostly supportive, and until now there are no clinically useful strategies for anti-inflammatory therapy. Although omega-3 polyunsaturated fatty acids (n-3 PUFA) are known to have anti-inflammatory effects, the utility of these fatty acids in the alleviation of pancreatitis remained to be investigated. The aim of this study was to examine the effect of n-3 PUFA on both acute and chronic pancreatitis in a well-controlled experimental system. We used the fat-1 transgenic mouse model, characterized by endogenously increased tissue levels of n-3 PUFA, and their wild-type littermates to examine the effect of n-3 PUFA on both acute and chronic cerulein-induced pancreatitis. Disease activity and inflammatory status were assessed by both histology and molecular methods. In acute pancreatitis, fat-1 mice showed a trend towards decreased necrosis and significantly reduced levels of plasma IL-6 levels as well as reduced neutrophil infiltration in the lung. In chronic pancreatitis there was less pancreatic fibrosis and collagen content accompanied by decreased pancreatic stellate cell activation in the fat-1 animals with increased n-3 PUFA tissue levels as compared to wild-type littermates with high levels of omega-6 (n-6) PUFA in their tissues. Our data provide evidence for a reduction of systemic inflammation in acute pancreatitis and of tissue fibrosis in chronic pancreatitis by increasing the tissue content of omega-3 polyunsaturated fatty acids. These results suggest a beneficial potential for n-3 PUFA supplementation in acute and particularly chronic pancreatitis.     

Relationships among Iron,Protein Oxidation and Lipid Peroxidation Levels in Rats with Alcohol-induced Acute Pancreatitis

It has been previously shown that alcohol induces the damage of pancreatic parenchyma tissue, but the mechanism of this damage is still poorly understood. Assuming that oxygen radical damage may be the involved, we measured markers of oxidative damage in pancreatic tissue, blood serum, plasma, and whole blood of rats with early-stage alcohol-induced acute pancreatitis. Thirty-eight male Wistar rats were divided into three groups: the control group (group 1), the acute pancreatitis group 1 day (group 2), and 3 days (group 3) after the injection of ethyl alcohol into the common biliary duct, respectively. The levels of Fe in tissue and serum, whole blood viscosity, plasma viscosity, fibrinogen and homocysteine (Hcy) levels, erythrocyte and plasma malondialdehyde (MDA), and tissue and plasma protein carbonyl levels were found to be significantly higher in groups 2 and 3 than in group 1. However, the levels of reduced glutathione (GSH) in tissue and erythrocytes were significantly lower in groups 2 and 3 than in group 1. These results suggest that elevated Fe levels in serum and pancreatic tissue in rats with early-stage alcohol-induced acute pancreatitis is associated with various hemorheological changes and with oxidative damage of the pancreas.     

Piperine ameliorates the severity of cerulein-induced acute pancreatitis by inhibiting the activation of mitogen activated protein kinases

Piperine is a phenolic component of black pepper (Piper nigrum) and long pepper (Piper longum), fruits used in traditional Asian medicine. Our previous study showed that piperine inhibits lipopolysaccharide-induced inflammatory responses. In this study, we investigated whether piperine reduces the severity of cerulein-induced acute pancreatitis (AP). Administration of piperine reduced histologic damage and myeloperoxidase (MPO) activity in the pancreas and ameliorated many of the examined laboratory parameters, including the pancreatic weight (PW) to body weight (BW) ratio, as well as serum levels of amylase and lipase and trypsin activity. Furthermore, piperine pretreatment reduced the production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 during cerulein-induced AP. In accordance with in vivo results, piperine reduced cell death, amylase and lipase activity, and cytokine production in isolated cerulein-treated pancreatic acinar cells. In addition, piperine inhibited the activation of mitogen-activated protein kinases (MAPKs). These findings suggest that the anti-inflammatory effect of piperine in cerulein-induced AP is mediated by inhibiting the activation of MAPKs. Thus, piperine may have a protective effect against AP.     

Effects of gabexate mesilate on serum inflammatory cytokines in rats with acute necrotizing pancreatitis

Gabexate mesilate is a synthetic protease inhibitor. The effectiveness of gabexate mesilate in patients with acute pancreatitis is controversial. Proinflammatory cytokines are associated with systemic inflammatory response syndrome (SIRS) in acute pancreatitis. A compensatory anti-inflammatory response occurs in parallel with SIRS. We investigated the effects of gabexate mesilate on acute necrotizing pancreatitis in rats, emphasizing the changes in serum levels of proinflammatory and anti-inflammatory cytokines. Acute necrotizing pancreatitis was induced by retrograde infusion of sodium taurodeoxycholate into the pancreatobiliary duct in rats. The rats were divided into three groups. Group I was given gabexate mesilate 2 mg/kg/h i.v. continuously 1 h before the induction of acute pancreatitis. Group II was given gabexate mesilate the same dose immediately after the induction of acute pancreatitis. Group III was given normal saline as the controls. Serum levels of amylase, lipase, tumor necrosis factor alpha, interleukin-6, and interleukin-10, pancreatic histopathology and hemodynamics were examined at 5h after the induction of acute pancreatitis. Gabexate mesilate significantly reduced serum levels of amylase, lipase, tumor necrosis factor alpha and interleukin-6 at 5 h. Serum levels of interleukin-10 significantly increased in Group I, as compared with Groups II and III. The severity of pancreatic histopathology, the reduction of mean arterial pressure, the volume of ascites and pancreatic wet weight/body weight ratios were also significantly improved by the administration of gabexate mesilate. The beneficial effects of gabexate mesilate on acute pancreatitis may be, in part, due to the modulation of inflammatory cytokine responses.     

Inhibition of the development of Schizophyllum commune germlings by the ammonium ion

Ammonium ions at a concentration of 1 mM completely inhibitthe growth and further development of 12–15 hr germlingsof Schizophyllum commune. The NH₄⁺, inhibition of germling growthis reversed by acetate and pyruvate, but it is reversed moreeffectively by TCA intermediates. Glucose, is not effectivein reversing the ammonium inhibition. From these data it isapparent that functional TCA enzymes are present in the germlingstage and that the mechanisms for incorporating acetate andpyruvate into the TCA cycle are also operative. There may be,however, an impaired glycolytic pathway, and, as a consequence,no intermediates are supplied to the TCA cycle, making the germlingssensitive to a disruption in the TCA cycle. The possible modeof action of ammonium ions is the activation of NADP-glutamatedehydrogenase, the subsequent enhancement of glutamic acid biosynthesis,and the final depletion of TCA intermediates. ¹This investigation was supported in part by Research GrantAI-06570 from the National Institute of Allergy and InfectiousDiseases of the U.S. Public Health Service (Received January 26, 1970; )     

Chemokine receptor CCR5 deficiency exacerbates cerulein-induced acute pancreatitis in mice

Acute pancreatitis (AP) is an inflammatory disease involving the production of different cytokines and chemokines and is characterized by leukocyte infiltration. Because the chemokine receptor CCR5 and its ligands [the CC chemokines CCL3/MIP-1alpha, CCL4/MIP-1beta, and CCL5/regulated upon activation, normal T cell expressed and secreted (RANTES)] regulate leukocyte chemotaxis and activation, we investigated the expression of CCR5 ligands and the role of CCR5 and its ligands in experimental AP in mice. AP was induced by hourly intraperitoneal injections of cerulein in CCR5-deficient (CCR5(-/-)) or wild-type (WT) mice. Induction of AP by cerulein resulted in an early increase of pancreatic CCL2, CCL3, and CCL4 mRNA expression, whereas CCL5 mRNA expression occurred later. CCR5(-/-) mice developed a more severe pancreatic injury than WT mice during cerulein-induced AP, as assessed by a more pronounced increase in serum amylase and lipase levels and by more severe pancreatic edema, inflammatory infiltrates (mainly neutrophils), and necrosis. CCR5(-/-) mice also exhibited increased production of CCL2/MCP-1, CCL3/MIP-1alpha, and CCL4/MIP-1beta during the course of cerulein-induced AP. In vivo simultaneous neutralization of CC chemokines with monoclonal antibodies in CCR5(-/-) mice reduced the severity of cerulein-induced AP, indicating a role of CC chemokines in exacerbating the course of AP in the absence of CCR5. Moreover, simultaneous neutralization of CCR5 ligands in WT mice also reduced the severity of cerulein-induced AP. In conclusion, lack of the chemokine receptor CCR5 exacerbates experimental cerulein-induced AP and leads to increased levels of CC chemokines and a more pronounced pancreatic inflammatory infiltrate, suggesting that CCR5 expression can modulate severity of AP.