Water immersion stress induces heat shock protein 60 expression and protects against pancreatitis in rats

Damage associated molecular patterns and neutrophil extracellular traps in acute pancreatitis

Previous researches have emphasized a trypsin-centered theory of acute pancreatitis (AP) for more than a century. With additional studies into the pathogenesis of AP, new mechanisms have been explored. Among them, the role of immune response bears great importance. Pro-inflammatory substances, especially damage-associated molecular patterns (DAMPs), play an essential role in activating, signaling, and steering inflammation. Meanwhile, activated neutrophils attach great importance to the immune defense by forming neutrophil extracellular traps (NETs), which cause ductal obstruction, premature trypsinogen activation, and modulate inflammation. In this review, we discuss the latest advances in understanding the pathological role of DAMPs and NETs in AP and shed light on the flexible crosstalk between these vital inflammatory mediators. We, then highlight the potentially promising treatment for AP targeting DAMPs and NETs, with a focus on novel insights into the mechanism, diagnosis, and management of AP.

Pre-inhalation of hydrogen-rich gases protect against caerulein-induced mouse acute pancreatitis while enhance the pancreatic Hsp60 protein expression

BACKGROUND

Acute pancreatitis (AP) lacks targeted prevention and treatment measures. Some key points in the pathogenesis of AP remain unclear, such as early activation of pancreatic enzymes. Several recent reports have shown the protective effect of hydrogen on several AP animal models, and the mechanism is related to antioxidant activity. Heat shock protein 60 (Hsp60) is known to accompany pancreatic enzymes synthesis and secretion pathway of in pancreatic acinar cells, while role of hsp60 in AP remains a topic. Aim of this study was to investigate effect of hydrogen pretreatment on AP and the mechanisms, focusing on pancreatic oxidative stress and Hsp60 expression.

METHODS

80 mice were randomly assigned into four groups: HAP group, AP group, HNS group, and NS group and each group were set 3 observation time point as 1 h, 3 h and 5 h (n = 6-8). Mouse AP model was induced by intraperitoneal injection of 50 μg/kg caerulein per hour for 6 injections both in AP and HAP groups, and mice in NS group and HNS group given normal saline (NS) injections at the same way as control respectively. Mice in HAP group and HNS group were treated with hydrogen-rich gases inhalation for 3 days before the first injection of caerulein or saline, while mice in AP group and NS group in normal air condition. Histopathology of pancreatic tissue, plasma amylase and lipase, plasma IL-1 and IL-6, pancreatic glutathione (GSH) and malondialdehyde (MDA), and Hsp60 mRNA and protein expression were investigated. Comparisons were made by one-way analysis of variance.

RESULTS

The pancreatic pathological changes, plasma amylase and lipase activity, and the increase of plasma IL-1 and IL-6 levels in AP mice were significantly improved by the hydrogen-rich gases pretreatment, Meanwhile, the pancreatic GSH content increased and the pancreatic MDA content decreased. And, the hydrogen-rich gases pretreatment improved the Hsp60 protein expression in pancreatic tissues of AP mice at 1 h and 5 h.

CONCLUSIONS

Pre-inhalation of hydrogen-rich gases have a good protective effect on AP mice, and the possible mechanisms of reduced oxidative stress and the early increased pancreatic Hsp60 protein deserve attention.

Increased heat shock protein 70 expression attenuates pancreatic fibrosis induced by dibutyltin dichloride

OBJECTIVES

Heat shock protein (HSP) 70 performs a chaperoning function and protects cells against injury. Although the effect of HSPs against acute inflammatory change has been proven, the relationship between HSP70 and chronic pancreatitis remains unclear. This study aimed to investigate the protective effect of increased HSP70 expression induced by thermal stress against pancreatic fibrosis in experimental chronic pancreatitis.

MATERIALS AND METHODS

Two experiments to evaluate pancreatic HSP70 expression induced by thermal stress and determine the effect of increased HSP70 expression against pancreatic fibrosis were performed. To investigate HSP70 expression, rats were immersed in a warm bath and sequentially killed, and pancreatic HSP70 expression was measured. To study the effect of increased HSP70 expression, pancreatic fibrosis was induced by intravenous injection of dibutyltin dichloride (DBTC) and analyzed under repeated thermal stress. The severity of pancreatic fibrosis was measured.

RESULTS

Thermal stress significantly increased HSP70 expression in the pancreas. HSP70 expression peaked at 6-12 h after warm bathing, and the increased HSP70 expression was associated with the attenuation of pancreatic fibrosis. Although pancreatic fibrosis was induced by DBTC injection, HSP70 expression induced by repeated thermal stress diminished the severity of atrophy and fibrosis. On western blot analysis, collagen type 1 expression was diminished in the increased HSP70 expression group, but not α-smooth muscle actin expression.

CONCLUSIONS

Thermal stress could increase pancreatic HSP70 expression, and induced HSP70 expression showed a protective effect against pancreatic fibrosis. Modulation of HSP70 expression could be a potential therapeutic target in the treatment of chronic pancreatitis.

Effect of Endotoxemia in Suckling Rats on Pancreatic Integrity and Exocrine Function in Adults: A Review Report

Background. Endotoxin (LPS), the component of Gram-negative bacteria, is responsible for sepsis and neonatal mortality, but low concentrations of LPS produced tissue protection in experimental studies. The effects of LPS applied to the suckling rats on the pancreas of adult animals have not been previously explored. We present the impact of neonatal endotoxemia on the pancreatic exocrine function and on the acute pancreatitis which has been investigated in the adult animals. Endotoxemia was induced in suckling rats by intraperitoneal application of LPS from Escherichia coli or Salmonella typhi. In the adult rats, pretreated in the early period of life with LPS, histological manifestations of acute pancreatitis have been reduced. Pancreatic weight and plasma lipase activity were decreased, and SOD concentration was reversed and accompanied by a significant reduction of lipid peroxidation products (MDA + 4 HNE) in the pancreatic tissue. In the pancreatic acini, the significant increases in protein signals for toll-like receptor 4 and for heat shock protein 60 were found. Signal for the CCK1 receptor was reduced and pancreatic secretory responses to caerulein were diminished, whereas basal enzyme secretion was unaffected. These pioneer studies have shown that exposition of suckling rats to endotoxin has an impact on the pancreas in the adult organism.

Delineation of Molecular Pathways Involved in Cardiomyopathies Caused by Troponin T Mutations

Familial hypertrophic cardiomyopathy (FHC) is associated with mild to severe cardiac problems and is the leading cause of sudden death in young people and athletes. Although the genetic basis for FHC is well-established, the molecular mechanisms that ultimately lead to cardiac dysfunction are not well understood. To obtain important insights into the molecular mechanism(s) involved in FHC, hearts from two FHC troponin T models (Ile79Asn [I79N] and Arg278Cys [R278C]) were investigated using label-free proteomics and metabolomics. Mutations in troponin T are the third most common cause of FHC, and the I79N mutation is associated with a high risk of sudden cardiac death. Most FHC-causing mutations, including I79N, increase the Ca(2+) sensitivity of the myofilament; however, the R278C mutation does not alter Ca(2+) sensitivity and is associated with a better prognosis than most FHC mutations. Out of more than 1200 identified proteins, 53 and 76 proteins were differentially expressed in I79N and R278C hearts, respectively, when compared with wild-type hearts. Interestingly, more than 400 proteins were differentially expressed when the I79N and R278C hearts were directly compared. The three major pathways affected in I79N hearts relative to R278C and wild-type hearts were the ubiquitin-proteasome system, antioxidant systems, and energy production pathways. Further investigation of the proteasome system using Western blotting and activity assays showed that proteasome dysfunction occurs in I79N hearts. Metabolomic results corroborate the proteomic data and suggest the glycolytic, citric acid, and electron transport chain pathways are important pathways that are altered in I79N hearts relative to R278C or wild-type hearts. Our findings suggest that impaired energy production and protein degradation dysfunction are important mechanisms in FHCs associated with poor prognosis and that cardiac hypertrophy is not likely needed for a switch from fatty acid to glucose metabolism.

p38 MAPK inhibition alleviates experimental acute pancreatitis in mice

BACKGROUND

The mitogen-activated protein kinases (MAPKs) signaling pathway is involved in inflammatory process. However, the mechanism is not clear. The present study was to investigate the role of p38 MAPK in acute pancreatitis in mice.

METHODS

Mice were divided into 4 groups: saline control; acute pancreatitis induced with repeated injections of cerulein; control plus p38 MAPK inhibitor SB203580; and acute pancreatitis plus SB203580. The pancreatic histology, pancreatic enzymes, cytokines, myeloperoxidase activity, p38 MAPK and heat shock protein (HSP) 60 and 70 were evaluated.

RESULTS

Repeated injections of cerulein resulted in acute pancreatitis in mice, accompanying with the activation of p38 MAPK and overexpression of HSP60 and HSP70 in the pancreatic tissues. Treatment with SB203580 significantly inhibited the activation of p38 MAPK, and furthermore, inhibited the expression of HSP60 and HSP70 in the pancreas, the inflammatory cytokines in the serum, and myeloperoxidase activity in the lung.

CONCLUSION

The p38 MAPK signaling pathway is involved in the regulation of inflammatory response and the expression of HSP60 and HSP70 in acute pancreatitis.

Cell death and DAMPs in acute pancreatitis

Cell death and inflammation are key pathologic responses of acute pancreatitis (AP), the leading cause of hospital admissions for gastrointestinal disorders. It is becoming increasingly clear that damage-associated molecular pattern molecules (DAMPs) play an important role in the pathogenesis of AP by linking local tissue damage to systemic inflammation syndrome. Endogenous DAMPs released from dead, dying or injured cells initiate and extend sterile inflammation via specific pattern recognition receptors. Inhibition of the release and activity of DAMPs (for example, high mobility group box 1, DNA, histones and adenosine triphosphate) provides significant protection against experimental AP. Moreover, increased serum levels of DAMPs in patients with AP correlate with disease severity. These findings provide novel insight into the mechanism, diagnosis and management of AP. DAMPs might be an attractive therapeutic target in AP.

Acute pancreatitis: The stress factor

Acute pancreatitis is an inflammatory disorder of the pancreas that may cause life-threatening complications. Etiologies of pancreatitis vary, with gallstones accounting for the majority of all cases, followed by alcohol. Other causes of pancreatitis include trauma, ischemia, mechanical obstruction, infections, autoimmune, hereditary, and drugs. The main events occurring in the pancreatic acinar cell that initiate and propagate acute pancreatitis include inhibition of secretion, intracellular activation of proteases, and generation of inflammatory mediators. Small cytokines known as chemokines are released from damaged pancreatic cells and attract inflammatory cells, whose systemic action ultimately determined the severity of the disease. Indeed, severe forms of pancreatitis may result in systemic inflammatory response syndrome and multiorgan dysfunction syndrome, characterized by a progressive physiologic failure of several interdependent organ systems. Stress occurs when homeostasis is threatened, and stressors can include physical or mental forces, or combinations of both. Depending on the timing and duration, stress can result in beneficial or harmful consequences. While it is well established that a previous acute-short-term stress decreases the severity of experimentally-induced pancreatitis, the worsening effects of chronic stress on the exocrine pancreas have received relatively little attention. This review will focus on the influence of both prior acute-short-term and chronic stress in acute pancreatitis.

Heat shock proteins and autophagy in rats with cerulein-induced acute pancreatitis

Background/Aims

Heat shock proteins (HSPs) protect rats from cerulein-induced acute pancreatitis (AP) by preventing the subcellular redistribution of cathepsin B and the activation of trypsinogen. Autophagy plays a critical role in the secretion of digestive enzymes and triggering of cerulein-induced AP via the colocalization of trypsinogen and lysosomes. Therefore, using a rat cerulein-induced AP model, we investigated whether HSPs prevent AP by regulating autophagy.

Methods

Twelve hours after fed standard laboratory chow and water, the experimental groups (cerulein, water-immersion [WI]-cerulein and heat-shock [HS]-cerulein) and the control groups (control, WI, and HS) received one intraperitoneal injection of cerulein (50 µg/kg) or saline, respectively. All of the rats were sacrificed at 6 hours after injection. The severity of the AP was assessed based on the serum amylase level and the histological and electron microscopy findings. Western blotting was also performed for HSP60/70 and LC3B-II.

Results

WI and HS induced HSP60 and HSP70, respectively. The induced HSP60/70 effectively prevented the development of cerulein-induced AP. Autophagy developed in the rats with cerulein-induced AP and was documented by the expression of LC3-II and electron microscopy findings. The WI-stressed rats and HS-treated rats did not develop cerulein-induced autophagy.

Conclusions

HSPs exert protective effects against cerulein-induced AP in rats by inhibiting autophagy.

Recent progress in understanding the pathogenesis of severe acute pancreatitis

Severe acute pancreatitis (SAP) is an acute abdominal disease that is characterized by sudden onset, quick progression, many complications and high mortality. Multiple organ dysfunction syndrome (MODS) is still regarded as the main cause of death in SAP patients. Nowadays, the mortality rate for patients with SAP in developed countries is 22.7%. In the early 21st century, the mortality reached 15.60%-23.77% in mainland China. However, the etiology, pathogenesis and pathophysiology of SAP remains unclear, resulting in puzzle or perplexity in choosing and developing treatment strategies for SAP. This paper reviews recent progress in understanding the pathogenesis of SAP.

Akt pathway is required for oestrogen-mediated attenuation of lung injury in a rodent model of cerulein-induced acute pancreatitis

BACKGROUND

The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) is known to be an endogenous negative feedback or compensatory mechanism that serves to limit pro-inflammatory and chemotactic events in response to injury. The aim of this study is to elucidate whether Akt plays any role in 17β-estradiol (E2)-mediated attenuation of lung injury after acute pancreatitis (AP).

MATERIALS AND METHODS

Male Sprague-Dawley rats underwent cerulein-induced AP. Rats were treated with vehicle (cyclodextrin), E2 (1 mg/kg body weight [BW]), or E2 plus PI3K/Akt inhibitor Wortmannin (100 μg/kg BW) 1h after the onset of AP. At 8 h after sham operation or AP, various parameters were measured.

RESULTS

AP led to a significant decrease in lung Akt phosphorylation, which was associated with increased lung tissue myeloperoxidase (MPO) activity, wet-to-dry weight ratios, interleukin (IL)-6, tumor necrosis factor (TNF)-α, cytokine-induced neutrophil chemoattractant (CINC)-1, and CINC-3 levels. Administration of E2 after AP restored the AP-induced decrease in Akt phosphorylation and attenuated the increase in lung injury markers (MPO activity and wet-to dry weight ratios) and pro-inflammatory mediator production. The effects of E2 on the lung were abolished by co-administration of Wortmannin.

CONCLUSIONS

These results collectively suggest evidences that the Akt pathway seems to be required for E2-mediated protection of lung injury after AP.

Down-regulation of HSP60 expression by RNAi increases lipopolysaccharide- and cerulein-induced damages on isolated rat pancreatic tissues

The objective of this study was to investigate the function of heat shock protein 60 (HSP60) on pancreatic tissues by applying HSP60 small interfering RNA (siRNA) to reduce HSP60 expression. Rat pancreas was isolated and pancreatic tissue snips were prepared, cultured, and stimulated with low and high concentrations of cerulein (10(-11) and 10(-5) mol/L) or lipopolysaccharide (LPS, 10 and 20 μg/mL). Before the stimulation and 1 and 4 h after the stimulation, the viability and the level of trypsinogen activation peptide (TAP) in the tissue fragments were determined and the levels of tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) in the culture supernatants were measured. Real-time PCR and Western blotting were used to evaluate the HSP60 mRNA and protein expression. After the administration of siRNA to inhibit HSP60 expression in the isolated tissues, these injury parameters were measured and compared. The pancreatic tissues in the control (mock-interfering) group showed a decreased viability to varying degrees after being stimulated with cerulein or LPS, and the levels of TAP, TNF-α, and IL-6 increased significantly (p < 0.05) in the tissues and/or in the culture supernatant. The expressions of HSP60 mRNA and protein were raised moderately after stimulating 1 h with low concentrations of cerulein or LPS, but decreased with high concentrations of the toxicants. In particular, the expression of HSP60 protein was reduced significantly (p < 0.05) when the tissues were stimulated by the two toxicants for 4 h. In contrast, the tissue fragments in which HSP60 siRNA was applied showed much lower tissue viability (p < 0.01) and higher levels of TNF-a, IL-6, and TAP (p < 0.01) in the tissues or culture supernatant after stimulating with the toxicants at the same dose and for the same time duration as compared with those of the control groups (p < 0.05). The results indicated that both cerulein and LPS can induce injuries on isolated pancreatic tissues, but the induction effects are dependent on the duration of the stimulation and on the concentrations of the toxicants. HSP60 siRNA reduces HSP60 expression and worsens the cerulein- or LPS-induced injuries on isolated pancreatic tissues, suggesting that HSP60 has a protective effect on pancreatic tissues against these toxicants.

Alteration and role of heat shock proteins in acute pancreatitis

Many etiological factors are involved in the pathogenesis of acute pancreatitis. The pathogenesis of acute pancreatitis has been attributed to such causes as trypsin autodigestion, pancreatic microcirculation malfunction, the calcium overload in pancreatic acinar cells, oxygen free radical injury, cytokine injury, and has been treated in detail in numerous reviews. More recently, heat shock proteins (HSP), particularly heat shock protein 60 (HSP60), have receive increasing attention as another possible factor in the pathogenesis and development of acute pancreatitis. This brief review aims to: (i) outline our current understanding of HSP and their role in pancreatitis; (ii) discuss the available evidences that suggest HSP's interplay between pancreas tissues and etiological agents; (iii) delineate the functional mechanisms of HSP proposed by different research groups, and offer new thinking in preventing and treating acute pancreatitis in general.

Ascitic fluid and serum from rats with acute pancreatitis injure rat pancreatic tissues and alter the expression of heat shock protein 60

Acute pancreatitis (AP) is an inflammatory process in which cytokines and chemokines are involved. After onset, extrapancreatic stimuli can induce the expression of cytokines in pancreatic acinar cells, thereby amplifying this inflammatory loop. To further determine the role and mechanism of irritating agents in the pathogenesis of AP, rat pancreatic tissues were stimulated with ascitic fluid (APa) and serum (APs) from rats with AP or with lipopolysaccharide (LPS). In addition, the alteration of heat shock protein 60 (HSP60) expression was evaluated. Rat pancreas was removed and meticulously snipped to fragments. The snips were cultured for up to 48 h. During this period, the tissue viability as well as amylase and TNF-alpha levels in the supernatant and the HSP60 expression in the pancreatic tissue before and after stimulation by APa, APs, and LPS were assayed time-dependently. At different time-points during the culture, the viability and the amylase activity in the pancreatic tissue remained largely stable. After stimulation with APa, APs, or LPS for 1 h, the pancreatic tissues showed some damage, and this was followed by a sharp decrease in the viability accompanied by increased levels of amylase and TNF-alpha in the culture medium 2 or 4 h after stimulation (p < 0.05). In contrast, both the HSP60 mRNA and protein levels had a relatively high expression in the freshly prepared tissue fragments (0 h). As the culturing period was extended, the expression of HSP60 mRNA decreased only slightly; at the same time, the HSP60 protein levels decreased over a prolonged culture time, significantly so from 12 through 48 h (p < 0.05). After stimulation with APs, APa, or LPS, both the expression of HSP60 mRNA and protein in the tissue fragments increased slightly at 1 h and decreased significantly thereafter at 2 and 4 h (p < 0.05). APa, APs, or LPS induce injuries on isolated pancreatic tissues, accompanied by an altered HSP60 expression pattern in a time-dependent manner.

Regulation of HSP60 and the role of MK2 in a new model of severe experimental pancreatitis

The objective of this study was to investigate the role of MAPKAP kinase 2 (MK2) and heat shock protein (HSP) HSP60 in the pathogenesis of a new model of severe acute pancreatitis (AP). MK2 plays a significant role in the regulation of cytokines. It has been shown that induction and expression of several HSPs can protect against experimental pancreatitis. Interplay between both systems seems of high interest. Mice with a homozygous deletion of the MK2 gene were used. Severe AP was induced by combined intraperitoneal injections of cerulein with lipopolysaccharide (LPS). Severity of AP was assessed by biochemical markers and histology. The serum IL-6 and lung myeloperoxidase (MPO) levels were determined for assessing the extent of systemic inflammatory response. Expression of HSP25, HSP60, HSP70, and HSP90 was analyzed by Western blotting. Repeated injections of cerulein alone or cerulein plus LPS (Cer+LPS) resulted in local inflammatory responses in the pancreas and corresponding systemic inflammatory changes with pronounced severity in the Cer+LPS group. Compared with the C57Bl wild-type mice, the MK2-/- mice presented with significant milder pancreatitis and attenuated responses of serum amylase and trypsinogen activity. Furthermore, serum IL-6 was decreased as well as lung MPO activity. Injection of LPS alone displayed neither pancreatic inflammatory responses nor alterations of pancreatic enzyme activities but evidently elevated serum IL-6 levels and increased lung MPO activity. In contrast hereto, in the MK2-/- mice, these changes were much milder. Increased expression of HSP25 and HSP60 occurred after induction of AP. Especially, HSP60 was robustly elevated after Cer+LPS treatment, in both MK2-/- and wild-type mice. Thus the homozygous deletion of the MK2 gene ameliorates the severity of acute pancreatitis and accompanying systemic inflammatory reactions in a new model of severe acute pancreatitis. Our data support the hypothesis that MK2 participates in the multifactorial regulation of early inflammatory responses in AP, independently of the regulation of stress proteins like HSP25 and HSP60 and most likely due to its effect on cytokine regulation.

Alteration of Cpn60 expression in pancreatic tissue of rats with acute pancreatitis

The expression of heat-shock protein 60 (also known as chaperonin 60, Cpn60) in experimental acute pancreatitis (AP) is considered to play an active role in the prevention of abnormal enzyme accumulation and activation in pancreatic acinar cells. However, there are controversial results in the literature regarding the relationship between the abnormality of Cpn60 expression and AP onset and development. The purpose of this study was to investigate the alternations of Cpn60 expression and the relationship between the abnormal expression of Cpn60 and AP progression in rat severe acute pancreatitis (SAP) models. In this report, we induced SAP in Sprague-Dawley (SD) rats by reverse injection of sodium deoxycholate into the pancreatic duct, and examined the dynamic changes of Cpn60 expression in pancreatic tissues from different time points and at different levels with techniques of real-time PCR, western blotting, and immunohistochemistry. At 1 h after SAP induction, the expression of Cpn60 mRNA in the AP pancreatic tissues was higher than those in the sham-operation group and normal control group, but decreased sharply as the time period was extended, and there was a significant difference between 1 h and 10 h after SAP induction (p < 0.05). In the AP process, Cpn60 protein expression showed transient elevation as well, and the increased protein expression occurred predominantly in affected, but not totally destroyed, pancreatic acinar cells. As AP progressed, the pancreatic tissues were seriously damaged, leading to a decreased overall Cpn60 protein expression. Our results show a complex pattern of Cpn60 expression in pancreatic tissues of SAP rats, and the causality between the damage of pancreatic tissues and the decrease of Cpn60 level needs to be investigated further.

Effects of bee venom on cholecystokinin octapeptide-induced acute pancreatitis in rats

OBJECTIVES

Bee venom (BV) has frequently been used as a remedy for inflammatory diseases. The aim of this study was to investigate the effect of BV on cholecystokinin octapeptide (CCK-8)-induced acute pancreatitis (AP) in rats.

METHODS

The BV pretreatment group: 0.25 mg/kg BV was administered subcutaneously, followed by 75 mug/kg CCK-8 subcutaneously 3 times after 1, 3, and 5 hours. This whole procedure was repeated for 5 days.

CONTROL GROUP

CCK-8 subcutaneously 3 times after 1, 3, and 5 hours for 5 days. The BV posttreatment group: CCK-8 subcutaneously 3 times at an interval of 2 hours for 3 days, and then 0.25 mg/kg of BV was administered subcutaneously.

CONTROL GROUP

CCK-8 subcutaneously 3 times at an interval of 2 hours for 3 days.

RESULTS

The BV pretreatment and posttreatment ameliorated many of the examined laboratory parameters (the pancreatic weight [PW]/body weight [BW] ratio, the serum amylase and lipase activity) and reduced histological damages in pancreas. Furthermore, BV pretreatment reduced the production of tumor necrosis factor-alpha, interleukin 1, and interleukin 6 and also decreased pancreatic nuclearfactor-kappaB binding activity compared with saline-treated group in the AP model. The BV also increased heat shock protein 60 (HSP60) and heat shock protein 72 (HSP72) compared with the saline-treated group in the AP model.

CONCLUSIONS

These findings suggest that the anti-inflammatory effect of BV in CCK-8-induced AP seems to be mediated by inhibiting nuclear factor-kappaB binding activity, and that BV may have a protective effect against AP.

Heat shock proteins in pancreatic diseases

Heat shock proteins (HSPs) are chaperone proteins that protect living cells against injury-inducing stimuli. Dysregulated expression of HSPs has been observed in various disease conditions including cancer. Using knock-out and transgenic animal approach, as well as standard, methods of heat shock protein 70 (HSP70) induction (i.e. thermal stress and arsenite administration), it has been shown that HSP70 protects against cell injury and acinar necrosis in experimental model of pancreatitis in animals. Animals in which HSP70 is induced prior to cerulein administration in a cerulein model of pancreatitis have reduced severity of pancreatitis, as demonstrated by lower serum amylase, lesser acinar necrosis on histology and decreased neutrophilic infiltration, suggesting that HSP70 is protective against cell death. Similar to the protective role of HSP70 in a pancreatitis model, HSP70 overexpression has been observed in pancreatic cancer and is believed to protect cancer cells from cell death. HSP70 is overexpressed both at mRNA and protein levels in pancreatic cancer cell lines as compared to normal pancreatic ductal cells. On a more clinical note, HSP70 is present in great abundance in pancreatic cancer clinical specimens as compared to normal pancreatic margins. Inhibition of HSP70 expression in pancreatic cancer cells leads to caspase-dependent apoptotic cell death and is a novel therapeutic modality for pancreatic cancer. Triptolide is a pharmacological agent which highly effective inhibiting HSP70 expression in pancreatic cancer cells and thus induces cell death. Moreover, triptolide is highly efficacious in reducing growth as well as locoregional spread of pancreatic tumors in an orthotopic model of pancreatic cancer and has tremendous potential as a novel therapeutic agent.

Sodium arsenite induces heat shock protein 70 expression and protects against secretagogue-induced trypsinogen and NF-kappaB activation

Heat shock proteins (HSPs), induced by a variety of stresses, are known to protect against cellular injury. Recent studies have demonstrated that prior beta-adrenergic stimulation as well as thermal or culture stress induces HSP70 expression and protects against cerulein-induced pancreatitis. The goal of our current studies was to determine whether or not a non-thermal, chemical stressor like sodium arsenite also upregulates HSP70 expression in the pancreas and prevents secretagogue-induced trypsinogen and NF-kappaB activation. We examined the effects of sodium arsenite preadministration on the parameters of cerulein-induced pancreatitis in rats and then monitored the effects of preincubating pancreatic acini with sodium arsenite in vitro. Our results showed that sodium arsenite pretreatment induced HSP70 expression both in vitro and in vivo and significantly ameliorated the severity of cerulein-induced pancreatitis, as evidenced by the markedly reduced degree of hyperamylasemia, pancreatic edema, and acinar cell necrosis. Sodium arsenite pretreatment not only inhibited trypsinogen activation and the subcellular redistribution of cathepsin B, but also prevented NF-kappaB translocation to the nucleus by inhibiting the IkappaBalpha degradation both in vivo and in vitro. We also examined the effect of sodium arsenite pretreatment in a more severe model of pancreatitis induced by L-arginine and found a similarly protective effect. Based on our observations we conclude that, like thermal stress, chemical stressors such as sodium arsenite also induce HSP70 expression in the pancreas and protect against acute pancreatitis. Thus, non-thermal pharmacologically induced stress can help prevent or treat pancreatitis.

Remote preconditioning reduces microcirculatory disorders in pancreatic ischemia/reperfusion injury

OBJECTIVES

Remote preconditioning (RPC) can protect from ischemia/reperfusion injury (IRI). We investigated the influence of RPC in pancreatic IRI.

METHODS

Wistar rats were randomized to 2 hours of ischemia and 2 hours of reperfusion of a pancreatic tail segment with or without 15 minutes of infrarenal ischemia 60 minutes before IRI. Microcirculatory measurements before ischemia and 1 and 2 hours after reperfusion included functional capillary density and leukocyte adherence in postcapillary venules, quantified by intravital fluorescence microscopy. Histology and tissue myeloperoxidase activity were further parameters of pancreatic injury.

RESULTS

Remote preconditioning caused an improvement of microcirculation (functional capillary density: 1 hour after reperfusion, 460 +/- 13 vs 350 +/- 9 cm/cm2; 2 hours after reperfusion, 437 +/- 13 vs 295 +/- 13 cm/cm2; P < 0.01) and reduced inflammatory tissue response (leukocyte adherence in postcapillary venules: 2 hours after reperfusion, 155 +/- 55 vs 748 +/- 187 cells/mm2; P < 0.01). Histology was significantly better in preconditioned animals (IR, 8.1+/- 1.3 score points; RPC, 6.2 +/- 1.3 score points; P < 0.05). The difference in myeloperoxidase activity was not significant (ischemia/reperfusion [IR], 105 +/- 72; RPC, 245 +/- 209 mU x min(-1) x mg(ti)(-1); P = 0.13).

CONCLUSIONS

With our dynamic functional microcirculatory measurements, we could demonstrate that RPC is a feasible method to reduce experimental pancreatic IRI. This was seen in an attenuation of nutritive tissue perfusion and a reduction of inflammatory tissue response and a lower histological damage. Because it is easy to perform before organ harvest, RPC could be a step to improve organ procurement in pancreas transplantation. Clinical studies are the next step to evaluate RPC in pancreas transplantation.

Why does pancreatic overstimulation cause pancreatitis?

Many animal models are available to investigate the pathogenesis of pancreatitis, an inflammatory disorder of the pancreas. However, the secretagogue hyperstimulation model of pancreatitis is the most commonly used. Animals infused with high doses of cholecystokinin (CCK) exhibit hyperamylasemia, pancreatic edema, and acinar cell injury, which closely mimic pancreatitis in humans. Intra-acinar zymogen activation is an essential early event in the pathogenesis of secretagogue-induced pancreatitis. Early in the course of pancreatitis, lysosomal hydrolases colocalize with digestive zymogens and activate them. These activated zymogens then cause acinar cell injury and necrosis, a characteristic of pancreatitis. Besides being the site of initiation of injury in pancreatitis, acinar cells also synthesize and release cytokines and chemokines very early in the course of pancreatitis, which then attract and activate inflammatory cells and initiate the disease's systemic phase.

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.

Loss of exocrine pancreatic stimulation during parenteral feeding suppresses digestive enzyme expression and induces Hsp70 expression

Luminal nutrients are essential for the growth and maintenance of digestive tissue including the pancreas and small intestinal mucosa. Long-term loss of luminal nutrients such as during animal hibernation has been shown to result in mucosal atrophy and a corresponding stress response characterized by the induction of heat shock protein (Hsp)70 expression. This study was conducted to determine if the loss of luminal nutrients during total parenteral nutrition (TPN) would result in atrophy of the exocrine pancreas and small intestinal mucosa as well as an induction of Hsp70 expression in rats. In experiment 1, the treatment groups included an orally fed control, a saline-infused surgical control, or TPN treatment for 7 days. In experiment 2, the treatment groups included an orally fed control and TPN alone or coinfused with varying doses of glucagon-like peptide (GLP)-2, a mucosal proliferation agent, for 7 days. In experiment 1, TPN resulted in a 40% reduction in pancreatic mass that was associated with a dramatic reduction in digestive enzyme expression, enhanced apoptosis, and a 200% increase in Hsp70 expression. Conversely, heat shock cognate 70, Hsp27, and Hsp60 expression was not changed in the pancreas. In experiment 2, TPN resulted in a 30% reduction in jejunal mucosa mass and a similar induction of Hsp70 expression. The inclusion of GLP-2 during TPN attenuated jejunal mucosal atrophy and inhibited Hsp70 expression, suggesting that Hsp70 induction is sensitive to cell growth. These data indicate that pancreatic and intestinal mucosal atrophy caused by a loss of luminal nutrient stimulation is accompanied by a compensatory response involving Hsp70.

Electroacupuncture protects against CCK-induced acute pancreatitis in rats

OBJECTIVE

Electroacupuncture (EA) has been used to treat myalgia, adiposis and gastroenteropathy in Korea. EA as a complementary and alternative medicine has been accepted worldwide mainly for the treatment acute and chronic pain and inflammation. The aim of this study was to investigate the effects of EA on acute pancreatitis induced by cholecystokinin octapeptide (CCK) in rats.

METHODS

Animals were divided into four groups: (1) a normal group; (2) a CCK-induced acute pancreatitis group; (3) a CCK-induced acute pancreatitis group treated with 100-Hz EA, and (4) a CCK-induced acute pancreatitis group treated with 2-Hz EA. High-frequency (100-Hz) and low-frequency EA (2-Hz) stimulations were applied to an acupoint equivalent to Zusanli (ST36) in rats, followed by 75 microg/kg CCK subcutaneously three times, after 1, 3 and 5 h. The entire procedure was repeated over 5 days. Repeated CCK treatment resulted in typical laboratory and morphological changes in experimentally induced pancreatitis.

RESULTS

EA significantly decreased the pancreatic weight/body weight ratio in CCK-induced acute pancreatitis, increased the pancreatic levels of HSP60 and HSP72, and decreased the beta-amylase and lipase levels associated with CCK-induced acute pancreatitis. Furthermore, the release of ACTH was increased in the blood serum of the EA-treated group.

CONCLUSION

EA may have protective effects against CCK-induced acute pancreatitis through the release of ACTH.

Alteration of chaperonin60 and pancreatic enzyme in pancreatic acinar cell under pathological condition

AIM

To investigate the changes of chaperonin60 (Cpn60) and pancreatic enzymes in pancreatic acinar cells, and to explore their roles in the development of experimental diabetes and acute pancreatitis (AP).

METHODS

Two different pathological models were replicated in Sprague-Dawley rats: streptozotocin-induced diabetes and sodium deoxycholate-induced AP. The contents of Cpn60 and pancreatic enzymes in different compartments of the acinar cells were measured by quantitative immunocytochemistry.

RESULTS

The levels of Cpn60 significantly increased in diabetes, but decreased in AP, especially in the zymogen granules of the pancreatic acinar cells. The elevation of Cpn60 was accompanied with the increased levels of pancreatic lipase and chymotrypsinogen in diabetes. However, a decreased Cpn60 level was accompanied by high levels of lipase and chymotrypsinogen in AP. The amylase level was markedly reduced in both the pathological conditions.

CONCLUSION

The equilibrium between Cpn60 and pancreatic enzymes in the acinar cells breaks in AP, and Cpn60 content decreases, suggesting an insufficient chaperone capacity. This may promote the aggregation and autoactivation of the premature enzymes in the pancreatic acinar cells and play roles in the development of AP.

Inhibitory effect of Patrinia scabiosaefolia on acute pancreatitis

AIM: To investigate the effect of Patrinia scabiosaefolia (PS) on the cholecystokinin (CCK) octapeptide- induced acute pancreatitis (AP) in rats.

METHODS: Wistar rats weighing 240-260 g were divided into three groups: (1) Normal saline-treated group; (2) treatment with PS at 100 mg/kg group, in which PS was administered orally, followed by subcutaneous administration of 75 µg/kg CCK octapeptide three times after 1, 3 and 5 h, and this whole procedure was repeated for 5 d; (3) treatment with saline group, in which the protocols were the same as in treatment group with PS. We determined the pancreatic weight/body weight ratio, the levels of pancreatic HSP60, HSP72 and the secretion of pro-inflammatory cytokines. Repeated CCK octapeptide treatment resulted in the typical laboratory findings of experimentally induced pancreatitis.

RESULTS: PS reduced the pancreatic weight/body weight ratio, the levels of serum amylase and lipase, and inhibited expressions of pro-inflammatory cytokines in the CCK octapeptide-induced AP. Furthermore, PS pretreatment increased the pancreatic levels of HSP60 and HSP72.

CONCLUSION: Pretreatment with PS has an anti-inflammatory effect on CCK octapeptide-induced AP.

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, lovastatin (statin) ameliorates CCK-induced acute pancreatitis in rats

Statin, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has an anti-inflammatory effect. The aim of this study was to investigate the effect of Lovastatin (statin) on the cholecystokinin-octapeptide (CCK)-induced acute pancreatitis in rats. In statin treated group, the pancreas weight/body weight (pw/bw) ratio in CCK-induced acute pancreatitis was significantly lower than DMSO-treated group. Statin also increased the pancreatic level of HSP 60. Additionally, the secretions of IL-1beta, TNF-alpha and IL-6 and the lipase levels were decreased in statin treated group. These results suggest that statin may play an important role in mitigating the progression of the inflammatory reactions during acute pancreatitis.

Spontaneous activation of pancreas trypsinogen in heat shock protein 70.1 knock-out mice

OBJECTIVES

Heat shock proteins (Hsp's) protect cellular proteins in response to injury, and the role of Hsp70 in experimental pancreatitis was recently described. To find out the possible role of Hsp70 in pancreatitis, we used Hsp70 knock-out mice (Hsp70.1-/-) and wild-type mice (Hsp70.1+/+).

METHODS

We studied enzymes activities, Hsp70 protein levels, and histologies in cerulein-induced pancreatitis of Hsp70.1-/- and Hsp70.1+/+ mice.

RESULTS

In the basal state, Hsp70 protein levels were higher in Hsp70.1+/+ than in Hsp70.1-/- mice, and trypsin activity was higher in Hsp70.1-/- than in Hsp70.1+/+ mice. The zymogen/lysosome ratio of cathepsin B activity before cerulein injection was higher in Hsp70.1-/- than in Hsp70.1+/+ mice. The expression level of Hsp70 in the pancreas increased in both of Hsp70.1-/- and Hsp70.1+/+ mice after hyperthermia because of the Hsp70.3 gene left intact in Hsp70.1-/- mice. After cerulein hyperstimulation, trypsin activity increased 2-fold in Hsp70.1+/+ mice, but cerulein did not further increase basally elevated trypsin activity in Hsp70.1-/- mice. Hyperthermia pretreatment not only blocked cerulein-induced trypsinogen activation, pancreatic edema, and vacuolization in Hsp70.1+/+ mice, but also decreased basally elevated trypsin activity in Hsp70.1-/- mice.

CONCLUSIONS

Hsp70 can be responsible for inhibition of cerulein-induced pancreatitis and prevention of spontaneous trypsinogen activation in mice by inhibiting the colocalization of zymogen and lysosomal enzymes.

Taraxacum officinale protects against cholecystokinin-induced acute pancreatitis in rats

AIM: Taraxacum officinale (TO) has been frequently used as a remedy for inflammatory diseases. The aim of this study was to investigate the effect of TO on cholecystokinin (CCK)-octapeptide-induced acute pancreatitis in rats.

METHODS: TO at 10 mg/kg was orally administered, followed by 75 μg/kg CCK octapeptide injected subcutaneously three times after 1, 3 and 5 h. This whole procedure was repeated for 5 d. We determined the pancreatic weight/body weight ratio, the levels of pancreatic HSP60 and HSP72, and the secretion of pro-inflammatory cytokines. Repeated CCK octapeptide treatment resulted in typical laboratory and morphological changes of experimentally-induced pancreatitis.

RESULTS: TO significantly decreased the pancreatic weight/body weight ratio in CCK octapeptide-induced acute pancreatitis. TO also increased the pancreatic levels of HSP60 and HSP72. Additionally, the secretion of IL-6 and TNF-α decreased in the animals treated with TO.

CONCLUSION: TO may have a protective effect against CCK octapeptide-induced acute pancreatitis.

Organ-specific stress induces mouse pancreatic keratin overexpression in association with NF-kappaB activation

Keratin polypeptides 8 and 18 (K8/K18) are the major intermediate filament proteins of pancreatic acinar cells and hepatocytes. Pancreatic keratin function is unknown, whereas hepatocyte keratins protect from mechanical and non-mechanical forms of stress. We characterized steady-state pancreatic keratin expression in Balb/c mice after caerulein and choline-deficient ethionine-supplemented diet (CDD), or on exposure to the generalized stresses of heat and water immersion. Keratins were studied at the protein, RNA and organizational levels. Isolated acini were used to study the role of nuclear factor (NF)-kappaB using selective inhibitors. Keratins were found to be abundant proteins making up 0.2%, 0.3% and 0.5% of the total cellular protein of pancreas, liver and small intestine, respectively. Caerulein and CDD caused a threefold transcription-mediated overall increase in K8/K18/K19/K20 proteins. Keratin overexpression begins on tissue recovery, peaks 2 days after caerulein injection, or 1 day after CDD discontinuation, and returns to basal levels after 10 days. K19/K20-containing cytoplasmic filaments are nearly absent pre-injury but form post-injury then return to their original membrane-proximal distribution after 10 days. By contrast, generalized stresses of heat or water-immersion stress do not alter keratin expression levels. Caerulein-induced keratin overexpression is associated with NF-kappaB activation when tested using ex vivo acinar cell cultures. In conclusion, keratins are abundant proteins that can behave as stress proteins in response to tissue-specific but not generalized forms of injury. Pancreatic keratin overexpression is associated with NF-kappaB activation and may serve unique functions in acinar or ductal cell response to injury.

Expression differences in mitochondrial and secretory chaperonin 60 (Cpn60) in pancreatic acinar cells

In pancreatic acinar cells, chaperonin Cpn60 is present in all the cellular compartments involved in protein secretion as well as in mitochondria. To better understand the role Cpn60 plays in pancreatic secretion, we have evaluated its changes under experimental conditions known to alter pancreatic secretion. Quantitative protein A-gold immunocytochemistry was used to reveal Cpn60 in pancreatic acinar cells. Cpn60 immunolabelings in cellular compartments involved in secretion were found to decrease in acute pancreatitis as well as upon stimulation of secretion and in starvation conditions. A major increase in Cpn60 was recorded in diabetic condition. This was normalized by insulin treatment. Although in certain situations changes in secretory enzymes and in Cpn60 correlate well, in others, nonparallel secretion seemed to take place. In contrast, expression of mitochondrial Cpn60 in acinar cells appeared to remain stable in all conditions except starvation, where its levels decreased. Expression of Cpn60 in the secretory pathway and in mitochondria thus appears to behave differently, and Cpn60 in the secretory pathway must be important for quality control and integrity of secretion.

Influence of stress in acute pancreatitis and correlation with stress-induced gastric ulcer

BACKGROUND AND AIMS

In the general adaptation syndrome, gastric lesions are the first manifestation of stress. We hypothesized that acute pancreatitis (AP), an inflammatory acute disease, will be exacerbated if unchained following stress. Visceral hypersensitivity will be enhanced due to catecholaminergic discharges leading to an over-induction of the intrapancreatic cholinergic tone with increased response of the pancreocyte to cholecystokinin (CCK). Our aim was to investigate the influence of stress before AP on the later AP, and the effect of AP on underlying diseases such as gastric ulceration.

METHODS

The model of stress induced by restraint was followed by the bilio-pancreatic duct outlet exclusion closed duodenal loops model. The effect of autonomous arc reflex (AAR) interruption by anesthetics after stress but before AP was assessed. The participation of the vagal and sympathetic pathways and involvement of CCK-A receptors were considered. The degree of severity was evaluated using biochemical and histopathological analyses.

RESULTS

Induction of AP after stress was more severe than in its absence. Acinar and fat necrosis, hemorrhage and neutrophil infiltrate foci were evenly distributed, being significantly greater in size and number after stress. Gastric ulceration evolved to ulcer, hemorrhage and gastric necrosis after AP triggering. Serum amylase, lipase, C-reactive protein, IL-6, IL-10 and plasmatic hsp72 as well as pancreatic and lung myeloperoxidase were significantly elevated in AP after stress while pancreatic amylase and lipase were significantly reduced. AAR blockage ameliorated AP after stress.

CONCLUSIONS

Stress aggravates pancreatic pathology while AP deteriorates gastric pathology, and anesthetic treatment was beneficial for both. Restraint in other animal models can be useful to study the influence of stress in the evolution of other diseases.

Overexpression of heat shock protein Hsp27 protects against cerulein-induced pancreatitis

BACKGROUND & AIMS

Heat shock protein (Hsp) 27 regulates actin cytoskeletal dynamics, and overexpression of Hsp27 in fibroblasts protects against stress in a phosphorylation-dependent manner. Induction of Hsps occurs in acute pancreatitis, but Hsp27 has not been ascribed a specific role. To examine whether Hsp27 would ameliorate acute pancreatitis, we generated transgenic mice overexpressing human Hsp27 (huHsp27) or Hsp27 with the phosphorylatable residues Ser(15,78,82) mutated to aspartic acid (huHsp27-3D) to mimic phosphorylation or to alanine (huHsp27-3A), which is nonphosphorylatable.

METHODS

huHsp27 was expressed at high levels in the exocrine pancreas by use of a cytomegalovirus promoter. Protein expression was analyzed by Western blotting and immunofluorescence. Acute pancreatitis was induced with 6 or 12 hourly cerulein injections (50 microg/kg intraperitoneally) and its severity assessed by measuring serum amylase and lipase levels, pancreatic trypsin activity, edema, and morphologic changes by quantitative scoring of multiple histologic sections and visualization of filamentous actin. Systemic inflammatory effects were monitored by measuring lung myeloperoxidase activity (a marker of neutrophil infiltration).

RESULTS

huHsp27 protein was overexpressed in the pancreas and localized to pancreatic acini. Acute pancreatitis was ameliorated by overexpression of huHsp27 and the huHsp27-3D mutant, which were associated with suppression of pancreatic trypsin activity and acinar cell injury and preservation of the actin cytoskeleton. In contrast, these changes were unaffected by overexpression of the nonphosphorylatable huHsp27-3A mutant.

CONCLUSIONS

Pancreatic overexpression of huHsp27 protects against cerulein-induced acute pancreatitis in a specific phosphorylation-dependent manner and is associated with preservation of the actin cytoskeleton.

Localization of VIP36 in the post-Golgi secretory pathway also of rat parotid acinar cells

VIP36 (36-kD vesicular integral membrane protein), originally purified from Madin-Darby canine kidney (MDCK) epithelial cells, belongs to a family of animal lectins and may act as a cargo receptor. To understand its role in secretory processes, we performed morphological analysis of the rat parotid gland. Immunoelectron microscopy provided evidence that endogenous VIP36 is localized in the trans-Golgi network, on immature granules, and on mature secretory granules in acinar cells. Double-staining immunofluorescence experiments confirmed that VIP36 and amylase co-localized in the apical regions of the acinar cells. This is the first study to demonstrate that endogenous VIP36 is involved in the post-Golgi secretory pathway, suggesting that VIP36 plays a role in trafficking and sorting of secretory and/or membrane proteins during granule formation.

Heat shock proteins and the pancreas

Heat shock proteins (HSPs) are cytoprotective molecules that help to maintain the metabolic and structural integrity of cells. In this review, we briefly discuss the regulation and function of HSPs. The review focuses on the current knowledge of pancreatic HSP induction, the HSP level changes during acute pancreatitis, the potential effects of the pre- and co-induction of HSPs in experimental acute pancreatitis, and the mechanisms by which HSPs might mediate cellular protection.

Deactivation of ROCK-II by Y-27632 enhances basolateral pancreatic enzyme secretion and acute pancreatitis induced by CCK analogues

In isolated rat pancreatic acini, protein expression of RhoA and Rho-associated kinase, ROCK-II, and the formation of immunocomplex of RhoA with ROCK-II were enhanced by CCK-8, carbachol, and the phorbol ester TPA. The ROCK-specific inhibitor, Y-27632, did not alter basal amylase secretion, whereas it potentiated CCK-stimulated pancreatic enzyme secretion in vitro. During caerulein-induced pancreatitis occurring in mice in vivo, Y-27632 enhanced serum amylase levels and the formation of interstitial edema and vacuolization at 12-18h after the first injection of caerulein. Y-27632 in turn inhibited the recovery of protein expression of ROCK-II at 18h after the first caerulein injection. These results suggest that RhoA and ROCK-II assemble normal CCK-stimulated pancreatic enzyme secretion and prevent caerulein-induced acute pancreatitis.

The gut origin of bacterial pancreatic infection during acute experimental pancreatitis in rats

BACKGROUND

Infections are frequent complications and determine clinical course and outcome in severe pancreatitis. A novel animal model was used to assess minimal transit time of bacterial translocation (BT) across the gut mucosa in vivo using green fluorescent protein-transfected Escherichia coli and intravital video microscopy.

METHODS

Three hours after induction of acute pancreatitis by i.p. injection of 40 microg/kg cerulein, 0.5 ml of a suspension of green fluorescent protein-transfected E. coli were injected into the lumen of a small bowel reservoir formed by ligature in anesthetized Wistar rats. Translocation of E. coli was assessed by intravital microscopy. Animals were sacrificed 5 h after induction of pancreatitis.

RESULTS

BT across the mucosa and into the muscularis propria took a mean +/- SD of 36.4 +/- 8 min and 80.9 +/- 9.5 min, respectively, in sham animals. Pancreatitis resulted in a significantly shorter minimal transit time across the mucosa (16.4 +/- 4.9 min, p = 0.007) and into the muscularis propria (47.7 +/- 2.5 min, p = 0.001). E. coli were detected on frozen cross-sections and on bacteriological examination of pancreatic tissue in animals with acute pancreatitis but not in controls.

DISCUSSION

Intravital microscopy of fluorescent bacteria is a new approach towards studying BT in vivo. Minimal transit time of BT serves as a novel functional aspect of mucosal barrier function during acute pancreatitis. The observation of fluorescent bacteria translocating from the small bowel lumen into the pancreas provides substantial experimental proof for the gut-origin-hypothesis of infectious complications in pancreatitis.

The anti-inflammatory effect of methylprednisolone occurs down-stream of nuclear factor-kappaB DNA binding in acute pancreatitis

Glucocorticoids are potent anti-inflammatory drugs. The molecular mechanisms underlying these effects have not yet been fully revealed. The aim of the present study was to establish whether methylprednisolone pretreatment is beneficial and if it can block the pancreatic DNA binding of the transcription factor nuclear factor-kappaB (NF-kappaB) and proinflammatory cytokine synthesis during cholecystokinin-octapeptide (CCK)-induced acute pancreatitis in rats. Additionally, we set out to investigate the potential effects of methylprednisolone and CCK on pancreatic heat shock protein (HSP) synthesis. The dose-response (5-40 mg/kg) and time-course (6-72 h) curves of methylprednisolone on pancreatic HSP60 and HSP72 synthesis were evaluated following methylprednisolone treatment. We demonstrated that methylprednisolone specifically and dose-dependently induced HSP72 in the pancreas of rats, while it did not have a significant effect on HSP60 expression. The pancreatitis was induced near the peak level of HSP72 synthesis (2 x 30 mg/kg body weight [b.w.] methylprednisolone i.m. at an interval of 12 h, followed by a 12-h recovery period after the second injection of methylprednisolone) by administering 2 x 100 microg/kg CCK subcutaneously at an interval of 1 h. The injections of CCK in the vehicle-pretreated group significantly elevated the levels of pancreatic HSP60 and HSP72 2-4 h after the second CCK injection. Methylprednisolone pretreatment ameliorated many of the examined laboratory (the pancreatic weight/body weight [p.w./b.w.] ratio, the serum amylase activity, the plasma trypsinogen activation peptide concentration, the pancreatic levels of tumor necrosis factor-alpha and interleukin-6, the degree of lipid peroxidation, protein oxidation, nonprotein sulfhydryl group content and the pancreatic myeloperoxidase activity) and morphological parameters of the disease. Methylprednisolone pretreatment did not influence pancreatic NF-kappaB DNA binding, but decreased proinflammatory cytokine synthesis in this acute pancreatitis model. The findings suggest that the anti-inflammatory effect of large doses of methylprednisolone in secretagogue-induced pancreatitis occurs downstream of NF-kappaB DNA binding, and that increased pancreatic HSP72 synthesis may play a role in the protective effect of the drug.

Can stress provide protection to pancreatic beta-cells and prevent diabetes?

A wide variety of stresses are prevalent in the environment that could change the course and phenotypic expression of metabolic diseases. Amongst the various stresses the oxidative stress plays a pivotal role in the disease progression through free radical generation and may lead to various metabolic disorders such as non-insulin dependent diabetes mellitus, cardiovascular diseases, hypertension obesity, stroke, etc. Psychological stress has been implicated as a root cause of several psychosomatic disorders. Thus there cannot be a life without stress. Under such a scenario of stressful conditions further fueled by life style changes we propose to counteract any kind of stress by another milder form of stress that is likely to protect the cells from drastic effects of severe stress. Here we hypothesize that the beta-cells of islets of Langerhans can be protected from the diabetogenic insults and oxidative stress by inducing a protective stress response such as heat shock through dietary interventions.

Expression differences in mitochondrial and secretory chaperonin 60 (Cpn60) in pancreatic acinar cells

In pancreatic acinar cells, chaperonin Cpn60 is present in all the cellular compartments involved in protein secretion as well as in mitochondria. To better understand the role Cpn60 plays in pancreatic secretion, we have evaluated its changes under experimental conditions known to alter pancreatic secretion. Quantitative protein A-gold immunocytochemistry was used to reveal Cpn60 in pancreatic acinar cells. Cpn60 immunolabelings in cellular compartments involved in secretion were found to decrease in acute pancreatitis as well as upon stimulation of secretion and in starvation conditions. A major increase in Cpn60 was recorded in diabetic condition. This was normalized by insulin treatment. Although in certain situations changes in secretory enzymes and in Cpn60 correlate well, in others, nonparallel secretion seemed to take place. In contrast, expression of mitochondrial Cpn60 in acinar cells appeared to remain stable in all conditions except starvation, where its levels decreased. Expression of Cpn60 in the secretory pathway and in mitochondria thus appears to behave differently, and Cpn60 in the secretory pathway must be important for quality control and integrity of secretion.

Comparative effects of water immersion pretreatment on three different acute pancreatitis models in rats

Cells respond to stress by upregulating the synthesis of cytoprotective heat shock proteins (HSPs) and antioxidant enzymes. The aim of this study was to compare the effects of cold (CWI) or hot water immersion (HWI) stress on three different acute pancreatitis models (cholecystokinin octapeptide (CCK), sodium taurocholate (TC), and L-arginine (Arg)). We examined the levels of pancreatic HSP60, HSP72, and antioxidants after the water immersion stress. Male Wistar rats were injected with CCK, TC, or Arg at the peak level of pancreatic HSP synthesis, as determined by Western blot analysis. HWI significantly elevated HSP72 expression and CWI significantly increased HSP60 expression in the pancreas. Water immersion stress decreased the levels of pancreatic antioxidants. CWI and-HWI pretreatment ameliorated most of the examined laboratory and morphological parameters of CCK-induced pancreatitis. CWI pretreatment decreased pancreatic edema and the serum amylase level; however, the morphological damage was more severe in TC-induced acute pancreatitis. Overall, CWI and HWI pretreatment only decreased the serum cytokine concentrations in Arg-induced pancreatitis. CWI and HWI resulted in differential induction of pancreatic HSP60 and HSP72 and the depletion of antioxidants. The findings suggest the possible roles of HSP60 and (or) HSP72 (but not that of the antioxidant enzymes) in the protection against CCK- and TC-induced acute pancreatitis. Unexpectedly, CWI pretreatment was detrimental to the morphological parameters of TC-induced pancreatitis. It was demonstrated that CWI and HWI pretreatment only influenced cytokine synthesis in Arg-induced pancreatitis.

From acinar cell damage to systemic inflammatory response: current concepts in pancreatitis

Acute pancreatitis represents a local inflammatory disorder with severe systemic consequences. Significant progress in understanding the pathophysiology of acute pancreatitis has been achieved in recent years. However, there is no clear concept about initialization and propagation of the disease both in experimental models and in humans. Furthermore, reliable strategies to evaluate prognosis and perform therapy are still missing. The review focuses on mechanisms originating from acinar cells leading to a systemic inflammatory response in experimental pancreatitis.

Nontoxic heat shock protein coinducer BRX-220 protects against acute pancreatitis in rats

BACKGROUND

Nontoxic heat shock protein (HSP) inducer compounds open up promising therapeutic possibilities by activating one of the natural and highly conserved defense mechanisms of the organism.

AIMS

In the present experiments, we examined the effects of a HSP coinducer drug-candidate, BRX-220, on the cholecystokinin-octapeptide (CCK)-induced acute pancreatitis in rats.

METHODS

Male Wistar rats weighing 240 to 270 g were divided into two groups. In group B, 20 mg/kg BRX-220 was administered orally, followed by 75 microg/kg CCK subcutaneously three times, after 1, 3, and 5 h. This whole procedure was repeated for 5 d. The animals in group slashed circleB received physiological saline orally instead of BRX-220, but otherwise the protocol was the same as in group B. The rats were exsanguinated through the abdominal aorta 12 h after the last administration of CCK. We determined the serum amylase activity, the plasma trypsinogen activation peptide concentration, the pancreatic weight/body weight ratio, the DNA and total protein contents of the pancreas, the levels of pancreatic HSP60 and HSP72, the activities of pancreatic amylase, lipase, trypsinogen, and free radical scavenger enzymes (superoxide dismutase, catalase, and glutathione peroxidase), the degree of lipid peroxidation, protein oxidation, and the reduced glutathione level. Histopathological investigation of the pancreas was also performed in all cases.

RESULTS

Repeated CCK treatment resulted in the typical laboratory and morphological changes of experimentally induced pancreatitis. The pancreatic levels of HSP60 and HSP72 were significantly increased in the animals treated with BRX-220. In group B, the pancreatic total protein content and the amylase and trypsinogen activities were significantly higher vs. group slashed circleB. The plasma trypsinogen activation peptide concentration, and the pancreatic lipid peroxidation, protein oxidation, and the activity of Cu/Zn-superoxide dismutase were significantly decreased in group B vs. group slashed circleB, whereas the glutathione peroxidase activity was increased. The morphological damage in group B was significantly lower than that in group slashed circleB.

CONCLUSION

The HSP coinducer BRX-220, administered for 5 d, has a protective effect against CCK-induced acute pancreatitis.