Reduction in the development of cerulein-induced acute pancreatitis by treatment with M40401, a new selective superoxide dismutase mimetic

Progress in research of liver injury induced by acute biliary pancreatitis

Acute biliary pancreatitis (ABP) not only causes acute inflammation of the pancreas, but also leads to obstruction or infection of the biliary system. Liver injury is one of the most common complications of ABP. The pathological mechanisms mainly include infection and endotoxin, cholestasis, pancreatic enzyme damage, microcirculatory disorders, and oxidative stress, and the research conclusions are mostly derived from animal experiments. On the basis of routine medical treatment of ABP, active anti-infective treatment and rapid relief of biliary obstruction can promote the recovery of ABP-related liver injury.

Carbon monoxide releasing molecule‑2 (CORM‑2)‑liberated CO ameliorates acute pancreatitis

The purpose of the present study was to investigate the effect of carbon monoxide (CO) released from CO‑releasing molecule 2 (CORM‑2) on mice with acute pancreatitis (AP). To perform the investigation, a mouse AP model was established using caerulein. The mice were treated with or without CORM‑2. The survival rate of the mice in the different groups was analyzed, and serum amylase and lipase levels were measured to assess the degree of pancreatic injury. The severity of AP was also evaluated by histological examination, and histopathological scoring of the pancreatic damage was performed. Pancreatic cell apoptosis was analyzed using a terminal deoxynucleotidyl‑transferase‑mediated dUTP nick end labelling assay. The function of the lung and liver was also assessed in the present study. Furthermore, the role of CORM‑2 on oxidative stress, intercellular adhesion molecule 1 (ICAM‑1) and vascular cell adhesion molecule 1 (VCAM‑1) expression, pro‑inflammatory cytokine production, and nuclear factor (NF)‑κB activation in the pancreas of AP mice was determined. The results demonstrated that CORM‑2 reduced the mortality, pancreatic damage, and lung and liver injury of AP mice. CORM‑2 administration also reduced systemic and localized inflammatory cell factors. Furthermore, treatment with CORM‑2 inhibited the expression of ICAM‑1 and VCAM‑1, and the activation of NF‑κB and phosphorylated inhibitor of NF‑κB subunit α, in the pancreas of AP mice. These results indicated that CO released from CORM‑2 exerted protective effects on AP mice, and the beneficial effects were likely due to inhibition of NF‑κB pathway activation.

Carbon monoxide releasing molecule‑2 (CORM‑2)‑liberated CO ameliorates acute pancreatitis

The purpose of the present study was to investigate the effect of carbon monoxide (CO) released from CO-releasing molecule 2 (CORM-2) on mice with acute pancreatitis (AP). To perform the investigation, a mouse AP model was established using caerulein. The mice were treated with or without CORM-2. The survival rate of the mice in the different groups was analyzed, and serum amylase and lipase levels were measured to assess the degree of pancreatic injury. The severity of AP was also evaluated by histological examination, and histopathological scoring of the pancreatic damage was performed. Pancreatic cell apoptosis was analyzed using a terminal deoxynucleotidyl-transferase-mediated dUTP nick end labelling assay. The function of the lung and liver was also assessed in the present study. Furthermore, the role of CORM-2 on oxidative stress, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) expression, pro-inflammatory cytokine production, and nuclear factor (NF)-κB activation in the pancreas of AP mice was determined. The results demonstrated that CORM-2 reduced the mortality, pancreatic damage, and lung and liver injury of AP mice. CORM-2 administration also reduced systemic and localized inflammatory cell factors. Furthermore, treatment with CORM-2 inhibited the expression of ICAM-1 and VCAM-1, and the activation of NF-κB and phosphorylated inhibitor of NF-κB subunit α, in the pancreas of AP mice. These results indicated that CO released from CORM-2 exerted protective effects on AP mice, and the beneficial effects were likely due to inhibition of NF-κB pathway activation.

Reappraisal of xenobiotic-induced, oxidative stress-mediated cellular injury in chronic pancreatitis: A systematic review

AIM: To reappraise the hypothesis of xenobiotic induced, cytochrome P450-mediated, micronutrient-deficient oxidative injury in chronic pancreatitis.

METHODS: Individual searches of the Medline and Embase databases were conducted for each component of the theory of oxidative-stress mediated cellular injury for the period from 1^st January 1990 to 31^st December 2012 using appropriate medical subject headings. Boolean operators were used. The individual components were drawn from a recent update on theory of oxidative stress-mediated cellular injury in chronic pancreatitis.

RESULTS: In relation to the association between exposure to volatile hydrocarbons and chronic pancreatitis the studies fail to adequately control for alcohol intake. Cytochrome P450 (CYP) induction occurs as a diffuse hepatic and extra-hepatic response to xenobiotic exposure rather than an acinar cell-specific process. GSH depletion is not consistently confirmed. There is good evidence of superoxide dismutase depletion in acute phases of injury but less to support a chronic intra-acinar depletion. Although the liver is the principal site of CYP induction there is no evidence to suggest that oxidative by-products are carried in bile and reflux into the pancreatic duct to cause injury.

CONCLUSION: Pancreatic acinar cell injury due to short-lived oxygen free radicals (generated by injury mediated by prematurely activated intra-acinar trypsin) is an important mechanism of cell damage in chronic pancreatitis. However, in contemporary paradigms of chronic pancreatitis this should be seen as one of a series of cell-injury mechanisms rather than a sole mediator.

Oxidative stress in acute pancreatitis: lost in translation?

Oxidative stress has been implicated in the pathogenesis of acute pancreatitis, a severe and debilitating inflammation of the pancreas that carries a significant mortality, and which imposes a considerable financial burden on the health system due to patient care. Although extensive efforts have been directed towards the elucidation of critical underlying mechanisms and the identification of novel therapeutic targets, the disease remains without a specific therapy. In experimental animal models of acute pancreatitis, increased oxidative stress and decreased antioxidant defences have been observed, changes also detected in patients clinically. However, despite the promise of studies evaluating the effects of antioxidants in these model systems, translation to the clinic has thus far been disappointing. This may reflect many factors involved in the design of both preclinical and clinical evaluations of antioxidant therapy, not least the fact that most experimental studies have focussed on pre-treatment rather than post-injury assessment. This review has examined evidence relating to the involvement of oxidative stress in the pathophysiology of acute pancreatitis, focussing on experimental models and the clinical experience, including the experimental techniques employed and potential of antioxidant therapy.

Inhibition of poly(ADP-ribose) polymerase attenuates acute kidney injury in sodium taurocholate-induced acute pancreatitis in rats

OBJECTIVES

The aim of our present study was to investigate the efficacy of poly(adenosine diphosphate-ribose) polymerase (PARP) inhibition in the development of acute kidney injury in an experimental model of severe acute pancreatitis induced by retrograde infusion of sodium taurocholate into the bile-pancreatic duct.

METHODS

Severity of pancreatitis was evaluated by serum amylase, lipase, tumor necrosis factor α, interleukin-1β, interleukin-6, and histological grading. The following markers of renal dysfunction and injury were measured: serum creatinine level, urea nitrogen level, myeloperoxidase activity, and histology. Activation of PARP, intercellular adhesion molecule-1, and P-selectin protein in the kidney was studied using Western blot analysis.

RESULTS

3-Aminobenzamide attenuated the following: (1) serum amylase, lipase, and renal dysfunction; (2) serum concentrations of proinflammatory cytokines; (3) pancreatic and renal pathological injury; (4) renal myeloperoxidase activity; and (5) activation of PARP, intercellular adhesion molecule-1, and P-selectin in the kidney.

CONCLUSIONS

Our results suggest that PARP activation may contribute to kidney injury and that PARP inhibitors may be beneficial in renal disorders associated with severe acute pancreatitis.

Development of a novel model of hypertriglyceridemic acute pancreatitis in hamsters: protective effects of probucol

OBJECTIVES

The aim of the present study was to develop a model of hypertriglyceridemic (HTG) acute pancreatitis and to investigate the effects of probucol in this model.

METHODS

Hamsters were fed a high-fat diet (HFD) or a normal diet for 3 weeks. Probucol was added at 1% to the HFD in the treated group. Pancreatitis was induced by 7 peritoneal injections of cerulein to the normal and HFD hamster groups. The severity of the pancreatitis and whole body oxidative stress were assessed.

RESULTS

The HFD induced severe HTG (>1000 mg/dL) in the hamsters. A more severe pancreatitis was observed in the HFD group. The HFD did not influence plasma-reduced glutathione level, but there was a significant increase after 1% probucol was provided in the diet. Plasma malonaldehyde levels in the HFD group were significantly higher than the normal chow group, whereas probucol administration significantly decreased plasma hydrogen peroxide and malonaldehyde levels. We also found that probucol significantly reduced levels of amylase and lipase in the plasma and pathological scores in pancreatic tissue.

CONCLUSIONS

This study presents a novel model of severe HTG acute pancreatitis, and our results support the potential therapeutic application of probucol in HTG acute pancreatitis.

Effects of mitogen-activated protein kinase signaling pathway inhibition on the development of cerulein-induced acute pancreatitis in mice

OBJECTIVES

Extracellular signal-regulated kinase (ERK) influences a number of pathways in all cells. The ERK cascade has long been known to be central to the activation of cellular processes such as proliferation, differentiation, and oncogenic transformation. The mitogen-activated protein (MAP) serine/threonine family of protein kinases, of which ERK is a member, is evolutionarily conserved and is activated by a mechanism that includes protein kinase cascades. The aim of this study was to investigate the effects of PD98059 [2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one], a highly selective inhibitor of MAP/ERK kinase 1 (MEK1) activation, on the development of acute pancreatitis.

METHODS

Pancreatitis was induced by intraperitoneal injection of cerulein (hourly × 5, 50 μg/kg) and PD98059 (10 mg/kg, 10% dimethylsulfoxide, intraperitoneally) was administrated 1 and 3 hours after cerulein administration.

RESULTS

Cerulein injection resulted in acute necrotizing pancreatitis. On the contrary, pancreatitis histological features, amylase, lipase, pancreas edema, and immunohistochemical staining for leukocyte adhesion molecules, transforming growth factor β, and apoptosis-related proteins were found reduced in PD98059-treated mice.

CONCLUSIONS

We propose that this study could help to clarify the role of MAPK in the regulation of the inflammatory process as acute pancreatitis.

The role of nitric oxide in the physiology and pathophysiology of the exocrine pancreas

SIGNIFICANCE

Nitric oxide (NO), a ubiquitous gaseous signaling molecule, contributes to both pancreatic physiology and pathophysiology.

RECENT ADVANCES

The present review provides a general overview of NO synthesis, signaling, and function. Further, it specifically discusses NO metabolism and its effects in the exocrine pancreas and focuses on the role of NO in the pathogenesis of acute pancreatitis and pancreatic ischemia/reperfusion injury.

CRITICAL ISSUES

Unfortunately, the role of NO in pancreatic physiology and pathophysiology remains controversial in numerous areas. Many questions regarding the messenger molecule still remain unanswered.

FUTURE DIRECTIONS

Probably the least is known about the downstream targets of NO, which need to be identified, especially at the molecular level.

Hyperbaric oxygen and N-acetylcysteine treatment in L-arginine-induced acute pancreatitis in rats

BACKGROUND

This study was designed to evaluate the combined effects of hyperbaric oxygen (HBO) and N-acetylcysteine (NAC) on acute necrotizing pancreatitis in rats.

METHODS

Experiments were performed in 50 male Wistar rats, which were divided into five groups (N = 10 for each group). The first group received normal saline (0.9% NaCl) intraperitoneal and served as the control group. In the second group, acute pancreatitis was induced by 3.2-g/kg body weight L-arginine intraperitoneal twice at an interval of 1 hr, which has been shown previously to produce severe necrotizing acute pancreatitis. In the third group, NAC treatment (1000 mg/kg) was given after 1 hr of the induction of acute pancreatitis twice 24 hr apart. In the fourth group, animals received HBO, 6 hr after the induction of pancreatitis twice 12 hr apart. In the fifth group, animals received together NAC as in Group 3 and HBO treatment as in Group 4. Groups 1, 2, and 3 were left under normal atmospheric pressures. Twelve hours after last treatment, the animals were killed by exsanguinations. Blood samples were studied for amylase, calcium, and lactate dehydrogenase (LDH), pancreatic histology, pancreatic tissue malondialdehyde, superoxide dismutase, and glutathione levels.

RESULTS

Acute pancreatitis is reduced by the treatment of NAC, HBO, NAC + HBO. HBO + NAC groups performed statistically the best in preventing L-arginine-induced acute necrotising pancreatitis.

CONCLUSIONS

NAC especially combined with HBO, decreases oxidative stress parameters, serum amylase, calcium, and LDH levels, as well as histopathologic score.

Pomalidomide suppresses cerulein-induced acute pancreatitis in mice

BACKGROUND

An overproduction of proinflammatory mediators in severe acute pancreatitis contributes to the systemic inflammatory response, which may lead to multiorgan damage and even death. Thus, inflammatory cytokines, e.g., tumor necrosis factor (TNF)-α and interleukin (IL)-1β, may be novel targets for the treatment of acute pancreatitis. The aim of this study was to investigate the therapeutic effects of pomalidomide (or CC-4047), a thalidomide analog and immunomodulatory agent, in acute pancreatitis.

METHODS

Acute pancreatitis was induced in C57BL/6 mice by intraperitoneal administration of cerulein (100 μg/kg/h × 8). Pomalidomide was administered (0.5 mg/kg orally) 1 h before the first or 1 h after the last cerulein administration. The severity of the acute pancreatitis was evaluated biochemically and morphologically.

RESULTS

Pretreatment with pomalidomide significantly reduced the plasma levels of amylase and lipase; the histological injury; and the expression of TNF-α, IL-1β, monocyte chemotactic protein-1 (MCP-1), and inducible nitric oxide synthase (iNOS) in cerulein-induced acute pancreatitis. Post-treatment with pomalidomide also decreased the cerulein-induced elevation of plasma amylase and lipase and decreased the pancreatic damage.

CONCLUSIONS

Treatment with pomalidomide ameliorated the severity of cerulein-induced acute pancreatitis in mice. Our data suggest that pomalidomide may become a new therapeutic agent in future clinical trials for the treatment of acute pancreatitis.

The glucocorticoid-induced TNF receptor family-related protein (GITR) is critical to the development of acute pancreatitis in mice

BACKGROUND AND PURPOSE

Pancreatitis represents a life-threatening inflammatory condition where leucocytes, cytokines and vascular endothelium contribute to the development of the inflammatory disease. The glucocorticoid-induced tumour necrosis factor (TNF) receptor family-related protein (GITR) is a costimulatory molecule for T lymphocytes, modulates innate and adaptive immune system and has been found to participate in a variety of immune responses and inflammatory processes. Our purpose was to verify whether inhibition of GITR triggering results in a better outcome in experimental pancreatitis.

EXPERIMENTAL APPROACH

In male GITR knock-out (GITR(-/-)) and GITR(+/+) mice on Sv129 background, acute pancreatitis was induced after i.p. administration of cerulein. Other experimental groups of GITR(+/+) mice were also treated with different doses of Fc-GITR fusion protein (up to 6.25 µg·mouse⁻¹), given by implanted mini-osmotic pump. Clinical score and pro-inflammatory parameters were evaluated.

KEY RESULTS

A less acute pancreatitis was found in GITR(-/-) mice than in GITR(+/+) mice, with marked differences in oedema, neutrophil infiltration, pancreatic dysfunction and injury. Co-treatment of GITR(+/+) mice with cerulein and Fc-GITR fusion protein (6.25 µg·mouse⁻¹) decreased the inflammatory response and tissue injury, compared with treatment with cerulein alone. Inhibition of GITR triggering was found to modulate activation of nuclear factor κB as well as the production of TNF-α, interleukin-1β, inducible nitric oxide synthase, nitrotyrosine, poly-ADP-ribose, intercellular adhesion molecule-1 and P-selectin.

CONCLUSIONS AND IMPLICATIONS

The GITR-GITR ligand system is crucial to the development of acute pancreatitis in mice. Our results also suggest that the Fc-GITR fusion protein could be useful in the treatment of acute pancreatitis.

Attenuation of Zn-induced acute pancreatitis in Wistar rat fed on Cu- and Mg- enriched modified poultry egg Psi

Zinc (Zn) consumption has increased in many populations either due to the increased intake of Zn-fortified foods as in the USA or in agricultural food stuffs as in some Indian states during the last decade. Its excessive intake has been reported to induce acute pancreatitis (AP) in many studies due to increase in oxidative stress that was further reported to cause Cu and Mg deficiencies. This led us to design a modified poultry egg (ME(Psi)) enriched with Cu and Mg along with other antioxidants, and its efficacy on Zn-induced AP was studied in male Wistar rats. In one set, the rats were fed on equacaloric semi-synthetic basal diet containing 20 mg Zn/kg diet (control, group I), and Zn-induced AP-I diet and AP-II diet containing 40 and 80 mg Zn/kg diet (groups II and III) for 180 days, respectively. In another set, the rats were initially fed on Zn-induced AP-I and AP-II diets for 90 days and then shifted to ME(Psi)-mixed Zn-induced AP-I and AP-II diets in groups IIME and IIIME for another 90 days. At the end of the experiment, data displayed increased serum and urinary Zn, Cu, and Mg levels in groups II and III rats, which were reduced and approached closer to control group I after ME(Psi) feeding in groups IIME and IIIME rats. Transmission electron microscopic studies of acinar cells revealed progressive dilation, vesicularization, and degeneration of endoplasmic reticulum (ER), and decrease in zymogen granules (ZG) in groups II and III rats in contrast to their curvilinear or concentric long parallel running cisternal profile of ER in control group I. The treatment of ME(Psi) helped in the restoration of the ER profile and ZG number, approaching closer to the control group I. The degree of recovery was dependent upon the degree of toxicity caused by the amount of Zn given in the diet. The results of this study suggest that ME(Psi)-mixed diet can protect the acinar cells from the deleterious effects of Zn by decreasing the oxidative stress.

Inhibition of Rac1 decreases the severity of pancreatitis and pancreatitis-associated lung injury in mice

Pancreatitis is a disease with high morbidity and mortality. In vitro experiments on pancreatic acini showed that supramaximal but not submaximal cholecystokinin (CCK) stimulation induces effects in the acinar cell that can be correlated with acinar morphological changes observed in the in vivo experimental model of cerulein-induced pancreatitis. The GTPase Rac1 was previously reported to be involved in CCK-evoked amylase release from pancreatic acinar cells. Here, we demonstrate that pretreatment with the Rac1 inhibitor NSC23766 (100 microM, 2 h) effectively blocked Rac1 translocation and activation in CCK-stimulated pancreatic acini, without affecting activation of its closely related GTPase, RhoA. This specific Rac1 inhibition decreased supramaximal (10 nM) CCK-stimulated acinar amylase release (27.% reduction), which seems to be connected to the reduction observed in serum amylase (46.6% reduction) and lipase levels (46.1% reduction) from cerulein-treated mice receiving NSC23766 (100 nmol h(-1)). The lack of Rac1 activation also reduced formation of reactive oxygen species (ROS; 20.8% reduction) and lactate dehydrogenase release (LDH; 24.3% reduction), but did not alter calcium signaling or trypsinogen activation in 10 nM CCK-stimulated acini. In the in vivo model, the cerulein-treated mice receiving NSC23766 also presented a decrease in both pancreatic and lung histopathological scores (reduction in oedema, 32.4 and 66.4%; haemorrhage, 48.3 and 60.2%; and leukocyte infiltrate, 53.5 and 43.6%, respectively; reduction in pancreatic necrosis, 65.6%) and inflammatory parameters [reduction in myeloperoxidase, 52.2 and 38.9%; nuclear factor kappaB (p65), 61.3 and 48.6%; and nuclear factor kappaB (p50), 46.9 and 44.9%, respectively], together with lower serum levels for inflammatory (TNF-alpha, 40.4% reduction) and cellular damage metabolites (LDH, 52.7% reduction). Collectively, these results suggest that pharmacological Rac1 inhibition ameliorates the severity of pancreatitis and pancreatitis-associated lung injury through the reduction of pancreatic acinar damage induced by pathological digestive enzyme secretion and overproduction of ROS.

Effects of thalidomide in a mouse model of cerulein-induced acute pancreatitis

Current knowledge shows that pathophysiology of acute pancreatitis is characterized by intraacinar enzyme activation and subsequent dysregulation in immune response. Interactions between leukocytes, soluble mediators such as cytokines and vascular endothelium contribute to the systemic progression of the inflammatory response, whose entity may--in the end--determine disease severity and outcome. Recently, it has been shown that TNF-[alpha] may be a novel target for the treatment of acute pancreatitis; but the role of thalidomide, an immunomodulatory agent that inhibits TNF-(alpha) and angiogenesis, has not been investigated so far. The aim of the present study was to assess the effects of thalidomide in a murine model of necrotizing acute pancreatitis. Necrotizing acute pancreatitis was induced in mice by intraperitoneal injection of cerulein (hourly, x5, 50 microg/kg); in another group of animals, thalidomide was administered (200 mg/kg orally) at 1 h after first cerulein injection. After 24 h, biochemical, histological, and immunohistochemical evidences of acute pancreatitis developed in all cerulein-treated mice. On the contrary, pancreatitis histological features, amylase, lipase, TNF-alpha and IL-1beta levels, pancreas edema, and myeloperoxidase activity as well as immunohistochemical staining for inflammatory cytokines, leukocyte adhesion molecules, transforming growth factor [beta], vascular endothelial growth factor, and apoptosis-related proteins were found reduced in thalidomide-treated mice. Therefore, thalidomide treatment attenuates the development of acute pancreatitis caused by cerulein in mice. We propose that this evidence may help to clarify the role of anti-TNF-alpha and immunomodulatory agents in patients with acute pancreatitis.

Effects of glycogen synthase kinase-3beta inhibition on the development of cerulein-induced acute pancreatitis in mice

OBJECTIVE

Glycogen synthase kinase (GSK)-3 is a ubiquitous serine-threonine protein kinase that participates in a multitude of cellular processes and signal transduction pathways. It also plays an important role in the pathophysiology of a number of diseases characterized by an enhanced or unregulated inflammatory response. Here we investigate the effects of GSK-3beta inhibition on the development of experimental acute pancreatitis induced by cerulein in mice.

DESIGN

Prospective, randomized study.

SETTING

University-based research laboratory.

SUBJECTS

One-hundred and sixty anesthetized male CD mice.

INTERVENTIONS

Pancreatitis was induced by intraperitoneal injection of cerulein (hourly x5, 50 microg/kg). In the treatment group, the potent and selective GSK-3beta inhibitor 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8) was administered 1 hr and 6 hrs after the first injection of cerulein (10 mg/kg, intraperitoneally). Sham groups were treated with vehicle (0.1 mL of 0.9% NaCl, intraperitoneally) and TDZD-8. In another set of experiments, mice were monitored for 24 days to determine their mortality rate.

MEASUREMENTS AND MAIN RESULTS

The injection of cerulein resulted in acute necrotizing pancreatitis. TDZD-8 significantly reduced the degree of pancreas injury, amylase, and lipase serum levels (p < .01); nuclear factor-kappaB activation (p < .01); the production of tumor necrosis factor-alpha and interleukin-1beta (p < .01); the expression of adhesion molecules and neutrophil accumulation (p < .01); the formation of oxygen and nitrogen-derived radicals (p < .01); the degree of lipid peroxidation (p < .01); the expression of transforming growth factor-beta and vascular endothelial growth factor (p < .01); and-ultimately-the mortality rate (p < .01).

CONCLUSIONS

Inhibition of GSK-3beta reduces the degree of cerulein-induced acute pancreatitis and the associated mortality rate in mice. Blocking protein kinase activity may be a novel approach to treatment of this inflammatory condition.

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.

Role of tumor necrosis factor-alpha in acute pancreatitis: from biological basis to clinical evidence

Tumor necrosis factor (TNF)-alpha is a pleiotropic cytokine that exerts host-damaging effects in different autoimmune and inflammatory diseases. It is a key regulator of other proinflammatory cytokines and of leukocyte adhesion molecules, and it is a priming activator of immune cells. In recent years, several research lines-mostly derived from animal models and in vitro studies-suggested that TNF-alpha plays a pivotal role in the pathogenesis of acute pancreatitis. In particular, it contributes to the systemic progression of the inflammatory response and to the end-organ dysfunction often observed in severe disease. Current clinical applications of TNF-alpha in acute pancreatitis include the assessment of blood concentrations to predict disease severity and to identify individuals prone to develop complications such as multiple organ failure and septic shock. However, TNF-alpha is rapidly cleared from the bloodstream, and sensitivity and overall accuracy of its measurement seem strictly time dependent, thereby being of potential prognostic value only in the first days after the onset of the disease. In parallel, TNF-alpha has been evaluated as a novel pharmacologic target for treating pancreatitis. Although promising results have been observed in the laboratory, transition to clinical practice seems problematic, in particular, in the light of divergent results obtained in sepsis trials. Therefore, in future clinical trials pertaining to TNF-alpha neutralization in acute pancreatitis, timing of intervention should be related to changes in TNF-alpha serum levels, and inclusion and exclusion criteria should be accurately selected to better define the population most likely to benefit.

Etanercept attenuates the development of cerulein-induced acute pancreatitis in mice: a comparison with TNF-alpha genetic deletion

TNF-alpha plays a pivotal role in the pathogenesis of acute pancreatitis. Recent studies have shown that TNF-alpha inhibition significantly ameliorates the course of experimental acute pancreatitis, but in this context, the effects of Etanercept, a novel anti-TNF-alpha agent, have not been investigated so far. The aims of the present study are (i) to assess the effects of pharmacological inhibition of TNF-alpha by means of Etanercept on the inflammatory response and apoptosis in a murine model of necrotizing acute pancreatitis and (ii) to compare the results to those observed in TNF-alpha receptor 1 knockout (TNFR1-KO) mice. Necrotizing acute pancreatitis was induced in TNF-alpha wild type for TNFR1 (WT) and TNFR1-KO mice by intraperitoneal injection of cerulein (hourly x5, 50 microg/kg). In another group of WT mice, Etanercept was administered (5 or 10 mg/kg, s.c.) at 1 h after first cerulein injection. Control groups received saline treatment. After 24 h, biochemical, histological, and immunohistochemical evidences of acute pancreatitis developed in all cerulein-treated mice; apoptosis was also present in the pancreas. Contrarily, pancreatitis histological features, amylase and lipase levels, pancreas water content, and myeloperoxidase activity were reduced in a similar degree in Etanercept-treated and TNFR1-KO mice. Likewise, in these two groups, immunohistochemical stainings and terminal deoxynucleotidyltransferase-mediated UTP nick-end labeling assay were found negative. TNF-alpha receptor 1 gene deletion and Etanercept administration ameliorate the course of experimental acute pancreatitis in a similar degree. Future studies on clinical applications of Etanercept in pancreatitis seem promising.

The Chinese herbal preparation Qing Yi Tang (QYT) improves intestinal myoelectrical activity and increases intestinal transit during acute pancreatitis in rodents

The aim was to investigate alterations of intestinal motility in models of acute pancreatitis and to investigate the effects of the Chinese herbal preparation Qing Yi Tang (QYT) on these alterations. Upper gastrointestinal transit was evaluated in mice following induction of mild acute pancreatitis (MAP) using caerulein. Myoelectrical activity was recorded in rats after induction of severe acute pancreatitis (SAP) using sodium deoxycholate (SDOC). The contractility of jejunum segments was evaluated in the presence of SDOC, lipopolysaccharide (LPS) and trypsin. QYT accelerated the transit in MAP mice in a concentration dependent manner. Slow wave activity of smooth muscle in rat stomach and jejunum remained unchanged following SAP, but the spiking activity was significantly decreased, with bursts of 7.2 +/- 2.6/10 min compared with 47.9 +/- 13.2/10 min without SAP (p < 0.01). QYT reversed this decrease. Additionally, the amplitudes of slow waves and spikes were enhanced by QYT in SAP rats. The tension and amplitude of spontaneous contractile activity was reduced by SDOC and LPS and increased by trypsin. Gastrointestinal (GI) transit is altered by SAP but not by MAP. The Chinese herbal preparation QYT improves disturbed motility in AP by stimulating myoelectrical activity and accelerating GI transit.

Oxidant-impaired intracellular Ca2+ signaling in pancreatic acinar cells: role of the plasma membrane Ca2+-ATPase

Pancreatitis is an inflammatory disease of pancreatic acinar cells whereby intracellular calcium concentration ([Ca(2+)](i)) signaling and enzyme secretion are impaired. Increased oxidative stress has been suggested to mediate the associated cell injury. The present study tested the effects of the oxidant, hydrogen peroxide, on [Ca(2+)](i) signaling in rat pancreatic acinar cells by simultaneously imaging fura-2, to measure [Ca(2+)](i), and dichlorofluorescein, to measure oxidative stress. Millimolar concentrations of hydrogen peroxide increased cellular oxidative stress and irreversibly increased [Ca(2+)](i), which was sensitive to antioxidants and removal of external Ca(2+), and ultimately led to cell lysis. Responses were also abolished by pretreatment with (sarco)endoplasmic reticulum Ca(2+)-ATPase inhibitors, unless cells were prestimulated with cholecystokinin to promote mitochondrial Ca(2+) uptake. This suggests that hydrogen peroxide promotes Ca(2+) release from the endoplasmic reticulum and the mitochondria and that it promotes Ca(2+) influx. Lower concentrations of hydrogen peroxide (10-100 muM) increased [Ca(2+)](i) and altered cholecystokinin-evoked [Ca(2+)](i) oscillations with marked heterogeneity, the severity of which was directly related to oxidative stress, suggesting differences in cellular antioxidant capacity. These changes in [Ca(2+)](i) also upregulated the activity of the plasma membrane Ca(2+)-ATPase in a Ca(2+)-dependent manner, whereas higher concentrations (0.1-1 mM) inactivated the plasma membrane Ca(2+)-ATPase. This may be important in facilitating "Ca(2+) overload," resulting in cell injury associated with pancreatitis.

Hydrogen peroxide-induced activation of defense mechanisms against oxidative stress in rat pancreatic acinar AR42J cells

Oxidative stress has been implicated in the pathogenesis of acute pancreatitis. Generally, cells respond to oxidative stress with adaptive changes in gene expression aimed at preventing cellular damage and increasing their survival. However, the overall extent of these genetic changes remains poorly defined. This issue was, therefore, examined in the current study. Following exposure of rat pancreatic AR42J cells to 0.08 mM hydrogen peroxide (H(2)O(2)), a concentration failing to induce necrotic cell death, the expression of 96 stress-related genes was monitored by cDNA microarray analysis. H(2)O(2) provoked a time-dependent reorientation of 54 genes. In particular, at 6 and 24 h, 27 and 11 genes were induced, whereas 10 and 6 genes were suppressed, respectively, showing that the degree of change was stronger at the early time point, and that the number of up-regulated genes was obviously larger than the number of down-regulated genes. Reverse transcription-PCR for selected genes confirmed the gene expression pattern. Many of the differentially up-regulated genes can be related to the antioxidant enzymatic defense system, to cell cycle arrest, to repair and/or replacement of damaged DNA, to repair of damaged protein, and to activation of the NF-kappaB pathway. The results suggest that AR42J cells respond to sublethal oxidative stress with transient transcriptional activation of multiple defense mechanisms that may be an indication for a complex adaptation process. An understanding of the cellular stress responses may lead to new insights into the pathogenesis of oxidative stress-related diseases including acute pancreatitis.

Effects of 3-aminobenzamide, an inhibitor of poly (ADP-ribose) polymerase, in a mouse model of acute pancreatitis induced by cerulein

Poly (ADP-ribose) polymerase (PARP), a nuclear enzyme activated by strand breaks in DNA, plays an important role in the colon injury associated with experimental colitis. The aim of the present study was to examine the effects of 3-aminobenzamide (3-AB), an inhibitor of PARP activity, in the development of acute pancreatitis caused by cerulein in 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 expression of the intercellular adhesion molecule-1 (ICAM-1) and P-selectin. Immunohistochemical examination demonstrated a marked increase in the staining (immunoreactivity) for transforming growth factor-beta (TGF-beta) and vascular endothelial growth factor (VEGF) in the pancreas of cerulein-treated mice in comparison to sham-treated mice. Acute pancreatitis in vehicle-treated mice was also associated with a significant mortality (40% survival at 5 days after cerulein administration). In contrast, (1) the degree of pancreatic inflammation and tissue injury (histological score), (2) upregulation/formation of ICAM-1 and P-selectin, (4) neutrophils infiltration and (5) the expression of TGF-beta and VEGF was markedly reduced in pancreatic tissue obtained from cerulein-treated mice which have been treated with 3-AB. These findings provide the evidence that PARP inhibition reduce the degree of pancreas injury caused by acute pancreatitis induced by cerulein administration.

Hypericum perforatum attenuates the development of cerulein-induced acute pancreatitis in mice

A considerable body of recent evidence suggests that oxidative stress and exaggerated production of reactive oxygen species play a major role in several aspects of inflammation and shock. Hypericum perforatum is a medicinal plant species containing many polyphenolic compounds, namely flavonoids and phenolic acids. Because polyphenolic compounds have high antioxidant potential, in this study we evaluated the effect of Hypericum perforatum extract on acute pancreatitis induced by cerulein administration in male CD mice. Intraperitoneal injection of cerulein in mice resulted in a severe, acute pancreatitis, which was characterized by edema, neutrophil infiltration, tissue hemorrhage, and cell necrosis as well as increases in the serum levels of amylase and/or lipase in comparison to sham-treated mice. The infiltration of the pancreatic tissue of these animals with neutrophils (measured as increase in myeloperoxidase activity) was associated with expression of the adhesion molecule ICAM-1. Immunohistochemical examination demonstrated a marked increase in the staining (immunoreactivity) for nitrotyrosine and poly(ADP-ribose) (PAR) in the pancreas of cerulein-treated mice in comparison to sham-treated mice. In contrast, the degree of (a) pancreatic inflammation and tissue injury (histological score), (b) expression of ICAM-1, (c) the staining for nitrotyrosine and PAR, and (d) myeloperoxidase activity was markedly reduced in pancreatic tissue sections obtained from cerulein-treated mice administered Hypericum perforatum extract (30 mg/kg, suspended in 0.2 mL of saline solution, o.s.). Moreover, the treatment with Hypericum perforatum extract significantly reduced the mortality rate at 5 days after cerulein administration. Taken together, our results indicate that Hypericum perforatum extract reduces the development of acute pancreatitis.

Free radicals and the pancreatic acinar cells: role in physiology and pathology

Reactive oxygen and nitrogen species (ROS and RNS) play an important role in signal transduction and cell injury processes. Nitric oxide synthase (NOS)-the key enzyme producing nitric oxide (NO)-is found in neuronal structures, vascular endothelium and, possibly, in acinar and ductal epithelial cells in the pancreas. NO is known to regulate cell homeostasis, and its effects on the acinar cells are reviewed here. ROS are implicated in the early events within the acinar cells, leading to the development of acute pancreatitis. The available data on ROS/RNS involvement in the apoptotic and necrotic death of pancreatic acinar cells will be discussed.

Role of peroxisome proliferator-activated receptor-alpha in acute pancreatitis induced by cerulein

The peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is a member of the nuclear receptor superfamily of ligand-dependent transcription factors related to retinoid, steroid and thyroid hormone receptors. The aim of the present study was to examine the effects of endogenous PPAR-alpha ligand on the development of acute pancreatitis caused by cerulein in mice. Intraperitoneal injection of cerulein into PPAR-alpha wild-type (WT) mice resulted in severe, acute pancreatitis characterized by oedema, neutrophil infiltration and necrosis and by elevated serum levels of amylase and lipase. Infiltration of pancreatic and lung tissue with neutrophils (measured as an increase in myeloperoxidase activity) was associated with enhanced expression of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and P-selectin. Immunohistochemical examination demonstrated a marked increase in the staining (immunoreactivity) for transforming growth factor-beta (TGF-beta) and vascular endothelial growth factor (VEGF) in the pancreas of cerulein-treated PPAR-alpha wild-type (WT) mice in comparison to sham-treated mice. Acute pancreatitis in PPAR-alphaWT mice was also associated with a significant mortality (20% survival at 5 days after cerulein administration). In contrast, the degree of pancreatic inflammation and tissue injury (histological score), up-regulation/formation of ICAM-1 and P-selectin, infiltration of neutrophils, and the expression of TGF-beta and VEGF was markedly enhanced in pancreatic tissue obtained from cerulein-treated PPAR-alpha knockout (KO) mice. Thus, endogenous PPAR-alpha ligands reduce the degree of pancreas injury caused by acute pancreatitis induced by cerulein administration.

Pancreatic acinar cell: its role in acute pancreatitis

The pancreatic acinar cell is the functional unit of the exocrine pancreas. It synthesizes, stores, and secretes digestive enzymes. Under normal physiological conditions, digestive enzymes are activated only once they have reached the duodenum. Premature activation of these enzymes within pancreatic acinar cells leads to the onset of acute pancreatitis; it is the major clinical disorder associated with pancreatic acinar cells. Although there have been major advances in our understanding of the pathogenesis of this disease in recent years, available treatment options are still limited to traditional nonspecific and palliative interventions. Novel therapeutic strategies have been suggested based on ongoing research in the physiology and pathophysiology of the disease; these include the administration of systemic antibiotics, antioxidants, cytokine antagonists, and more recently, inhibition of the renin-angiotensin system. Notwithstanding this promising development, most of these potential therapies are still in an experimental stage or clinical trial. Further investigation is needed to prove the efficacy of these novel treatment modalities.

Oxidative-nitrosative stress and poly(ADP-ribose) polymerase (PARP) activation in experimental diabetic neuropathy: the relation is revisited

Poly(ADP-ribose) polymerase (PARP) activation, an important factor in the pathogenesis of diabetes complications, is considered a downstream effector of oxidative-nitrosative stress. However, some recent findings suggest that it is not necessarily the case and that PARP activation may precede and contribute to free radical and oxidant-induced injury. This study evaluated the effect of PARP inhibition on oxidative-nitrosative stress in diabetic peripheral nerve, vasa nervorum, aorta, and high glucose-exposed human Schwann cells. In vivo experiments were performed in control rats and streptozocin (STZ)-induced diabetic rats treated with and without the PARP inhibitor 3-aminobenzamide (ABA) (30 mg . kg(-1) . day(-1) i.p. for 2 weeks after 2 weeks of untreated diabetes). Human Schwann cells (HSC) (passages 7-10; ScienCell Research Labs) were cultured in 5.5 or 30 mmol/l glucose with and without 5 mmol/l ABA. Diabetes-induced increase in peripheral nerve nitrotyrosine immunoreactivity, epineurial vessel superoxide and nitrotyrosine immunoreactivities, and aortic superoxide production was reduced by ABA. PARP-1 (Western blot analysis) was abundantly expressed in HSC, and its expression was not affected by high glucose or ABA treatment. High-glucose-induced superoxide production and overexpression of nitrosylated and poly(ADP-ribosyl)ated protein, chemically reduced amino acid-(4)-hydroxynonenal adducts, and inducible nitric oxide synthase were decreased by ABA. We concluded that PARP activation contributes to superoxide anion radical and peroxynitrite formation in peripheral nerve, vasa nervorum, and aorta of STZ-induced diabetic rats and high- glucose-exposed HSC. The relations between oxidative-nitrosative stress and PARP activation in diabetes are bi- rather than unidirectional, and PARP activation cannot only result from but also lead to free radical and oxidant generation.

Flurbiprofen and HCT1026 protect mice against acute pancreatitis-associated lung injury

Impaired lung function in severe acute pancreatitis is the primary cause of morbidity and mortality in this condition. Flurbiprofen is a powerful nonsteroidal anti-inflammatory drug (NSAID). However, administration of this drug is associated with severe gastrointestinal side effects. The NO-releasing derivative of flubiprofen (nitroflurbiprofen, HCT1026) has recently been developed by the addition of a nitroxybutyl moiety to the flurbiprofen structure. This modification does not interfere with the anti-inflammatory activity of the drug but markedly reduces its ability to induce gastric injury. The effects of treatment with flurbiprofen and HCT1026 on the severity of pancreatitis and the associated lung injury were investigated in a mouse model. Acute pancreatitis was induced in mice by hourly intraperitoneal injections of cerulein. Flurbiprofen and HCT1026 were administered either 30 min before or 1 h after starting cerulein injections, and the severity of acute pancreatitis and associated lung injury were assessed. The severity of acute pancreatitis was determined by hyperamylasemia, neutrophil sequestration in the pancreas (pancreatic MPO activity), and pancreatic acinar cell injury/necrosis on histological examination of pancreas sections. The severity of acute pancreatitis-associated lung injury was assessed by neutrophil sequestration in the lungs (lung MPO activity) and by histological examination of lung sections. HCT1026 and flurbiprofen, given prophylactically as well as therapeutically, significantly reduced lung inflammation without having any significant effect on pancreatic injury. These results suggest the usefulness of flurbiprofen as well as HCT1026 as potential treatments for pancreatitis-associated lung injury.