L-arginine-induced experimental pancreatitis

Oregano (Origanum vulgare) Essential Oil and Its Constituents Prevent Rat Kidney Tissue Injury and Inflammation Induced by a High Dose of L-Arginine

This study aimed to evaluate the protective action of oregano (Origanum vulgare) essential oil and its monoterpene constituents (thymol and carvacrol) in L-arginine-induced kidney damage by studying inflammatory and tissue damage parameters. The determination of biochemical markers that reflect kidney function, i.e., serum levels of urea and creatinine, tissue levels of neutrophil-gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1), as well as a panel of oxidative-stress-related and inflammatory biomarkers, was performed. Furthermore, histopathological and immunohistochemical analyses of kidneys obtained from different experimental groups were conducted. Pre-treatment with the investigated compounds prevented an L-arginine-induced increase in serum and tissue kidney damage markers and, additionally, decreased the levels of inflammation-related parameters (TNF-α and nitric oxide concentrations and myeloperoxidase activity). Micromorphological kidney tissue changes correlate with the alterations observed in the biochemical parameters, as well as the expression of CD95 in tubule cells and CD68 in inflammatory infiltrate cells. The present results revealed that oregano essential oil, thymol, and carvacrol exert nephroprotective activity, which could be, to a great extent, associated with their anti-inflammatory, antiradical scavenging, and antiapoptotic action and, above all, due to their ability to lessen the disturbances arising from acute pancreatic damage. Further in-depth studies are needed in order to provide more detailed explanations of the observed activities.

Probiotics mixture and taurine attenuate L-arginine-induced acute pancreatitis in rats: Impact on transient receptor potential vanilloid-1 (TRPV-1)/IL-33/NF-κB signaling and apoptosis

Acute pancreatitis (AP) is an inflammatory disorder of acinar cells. It may develop into severe chronic pancreatitis with a significant mortality rate. The current study aimed to assess the therapeutic effect of a Lactobacillus (LAB) mixture against rat AP. Six groups were created including control, taurine (300 mg/kg; i.p.) for 7 days, LAB mixture for 7 days, L-arginine (2.5 g/kg; i.p.) 2 doses with 1 h interval on 1st day, L-arginine+taurine, and L-arginine+LAB. Serum amylase and lipase activities were measured. Pancreatic tissue was used for histopathological examination, oxidative stress biomarkers including malondialdehyde (MDA) and reduced glutathione (GSH), and inflammatory biomarkers including myeloperoxidase (MPO) and interleukin (IL)-33 assessment. qRT-PCR was used for transient receptor potential vanilloid-1 (TRPV-1) investigation and Western blot analysis for measuring nuclear factor kappa-B (NF-κBp65) and the apoptosis biomarker; caspase-3. Taurine and LAB reduced lipase and significantly ameliorated induced oxidative stress by normalizing MDA and GSH contents. They counteracted inflammation by reducing MPO, IL-33, NF-κBp65, and TRPV-1. In addition, taurine and LAB counteracted apoptosis as proved by reduced caspase-3 expression. Taken together, these findings indicate that taurine and the use LAB mixture can mitigate AP by L-arginine via influencing TRPV-1/IL-33/NF-κB signaling together with exhibiting potent antioxidant and anti-inflammatory effects.

Polystyrene microplastics aggravate acute pancreatitis in mice

Microplastics (MPs) with a diameter of < 5mm are emerging as a new type of environmental pollutants. With the discovery of MPs in human tissues, the health risks of MPs have attracted considerable attention in recent years. In this study, we aimed to investigate the impact of MPs on acute pancreatitis (AP). We exposed male mice to 100 and 1000μg/L polystyrene MPs for 28 days, then intraperitoneally injected mice with cerulein to develop acute pancreatitis (AP). The results demonstrated that MPs dose-dependently exacerbated pancreatic injuries and inflammation in AP. High-dose MPs significantly increased intestinal barrier disruption in AP mice, which may be partly responsible for the aggravation of AP. Moreover, through tandem mass tag (TMT)- based proteomics of pancreatic tissues, we screened 101 differentially expressed proteins (DEPs) between AP mice and high-dose MPs-treated AP mice. Gene Ontology and KEGG Pathway analysis revealed that the DEPs were mainly implicated in the molecular events including cytoskeleton organization, acute inflammatory response, arginine metabolism, etc. These mechanisms may also contribute to the aggravating AP effects of MPs. Collectively, our data provide new evidence for the harmful potential of MPs.

Vitamin E protects against the modulation of TNF-α-AMPK axis and inhibits pancreas injury in a rat model of L-arginine-induced acute necrotising pancreatitis

BACKGROUND

Acute pancreatitis (AP) associated with the modulation of TNF-α-AMPK axis in the presence and absence of vitamin E has not been investigated before.

MATERIAL AND METHODS

Rats were either injected with L-arginine (2.5 gm/kg) before being sacrificed after 48 h or were pre-treated with vitamin E (60 mg/kg) and continued receiving vitamin E until the end of the experiment.

RESULTS

AP was developed as demonstrated by infiltration of inflammatory cells and profound pancreas tissue damage, which were substantially protected by vitamin E. In addition, L-arginine injections significantly (p < .0001) increased the expression of TNF-α mRNA and protein, and decreased phospho-AMPK and IL-10 mRNA and protein that was significantly (p < .0001) protected by vitamin E. Furthermore, vitamin E inhibited L-arginine-induced blood levels of LDH, amylase, and myeloperoxidase.

CONCLUSIONS

L-arginine-induced acute pancreatitis modulates TNF-α-AMPK axis, IL-10 and other AP biomarkers, which is protected by vitamin E; thus, may offer therapeutic potential in humans.

Reorienting of pramipexole as a promising therapy for acute pancreatitis in a rat model by suppressing TLR-4\NF-κB p65\NLRP3 inflammasome signaling

OBJECTIVE

Acute pancreatitis (AP), a disorder of global importance, has a growing incidence and prevalence, particularly in the western world. Its complications include pseudo-cysts and chronic pancreatitis. Pramipexole (PMX), a D2/3 receptor selecting agonist used in Parkinsonism, has reported anti-inflammatory effects lately.

PURPOSE

Exploring the potential curative role of PMX in an l-arginine-induced acute pancreatitis rat model besides a possible mechanistic pathway.

METHODS

Rats were divided randomly into three groups: control, l-arginine, and "l-arginine + PMX". 7 days after AP induction, rats decapitated and estimated for serum amylase, lipase, glucose, pancreatic inflammatory mediators "toll-like receptor-4, nuclear factor- kappa B p65 ,serum tumor necrosis factor-α, NLRP3 inflammasome, caspase-1, interleukin-1 beta, oxidative biomarkers "malondialdehyde, myeloperoxidase, nitrite/nitrate, reduced glutathione, and the apoptotic marker "caspase-3", with pancreatic histopathological changes.

RESULTS

L-arginine mediated AP proved by elevated serum lipase and amylase, pancreatic inflammatory, oxidative and apoptotic markers with infiltration of inflammatory cells using hematoxylin and eosin stain. PMX improved all these adverse signs of AP greatly.

CONCLUSION

PMX might be considered as an innovative therapy for AP due to its remarkable antioxidant, anti-apoptotic, and anti-inflammatory effects, which are attributed to the suppression of the NLRP3 inflammasome and its downstream inflammatory cytokines.

Hypertriglyceridemia Acute Pancreatitis: Animal Experiment Research

In recent years, the number of acute pancreatitis cases caused by hypertriglyceridemia has increased gradually, which has caught the attention of the medical community. However, because the exact mechanism of hypertriglyceridemic acute pancreatitis (HTG-AP) is not clear, treatment and prevention in clinical practice face enormous challenges. Animal models are useful for elucidating the pathogenesis of diseases and developing and testing novel interventions. Therefore, animal experiments have become the key research means for us to understand and treat this disease. We searched almost all HTG-AP animal models by collecting many studies and finally collated common animals such as rats, mice and included some rare animals that are not commonly used, summarizing the methods to model spontaneous pancreatitis and induce pancreatitis. We sorted them on the basis of three aspects, including the selection of different animals, analyzed the characteristics of different animals, different approaches to establish hypertriglyceridemic pancreatitis and their relative advantages and disadvantages, and introduced the applications of these models in studies of pathogenesis and drug therapy. We hope this review can provide relevant comparisons and analyses for researchers who intend to carry out animal experiments and will help researchers to select and establish more suitable animal experimental models according to their own experimental design.

A Severe Acute Pancreatitis Mouse Model Transited from Mild Symptoms Induced by a “Two-Hit” Strategy with L-Arginine

To develop a severe acute pancreatitis (SAP) model transited from mild symptoms, we investigated a “two-hit” strategy with L-arginine in mice. The mice were intraperitoneally injected with ice-cold L-arginine (4 g/kg) twice at an interval of 1 h on the first day and subjected to the repeated operation 72 h afterwards. The results showed the “two-hit” strategy resulted in the destructive damage and extensive necrosis of acinar cells in the pancreas compared with the “one-hit” model. Meanwhile, excessive levels of pro-inflammatory mediators, namely IL-6 and TNF-α, were released in the serum. Remarkably, additional deleterious effects on multiple organs were observed, including high intestinal permeability, kidney injury, and severe acute lung injury. Therefore, we confirmed that the SAP animal model triggered by a “two-hit” strategy with L-arginine was successfully established, providing a solid foundation for a deeper understanding of SAP initiation and therapy research to prevent worsening of the disease.

Trimethylamine N-oxide promotes hyperlipidemia acute pancreatitis via inflammatory response

Trimethylamine N-oxide (TMAO), a metabolite of gut microbiota, is involved in the regulation of lipid metabolism and inflammatory response; however, the role of TMAO in hyperlipidemia acute pancreatitis (HAP) is not clear. In this study, HAP mice were used as an animal model to explore the effects and possible mechanism of TMAO on HAP, which may provide new ideas for the treatment of HAP. Results found that the levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol, nonestesterified fatty acid, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, α-amylase, TMAO, and flavin-containing monooxygenase 3 were significantly increased, the levels of high-density lipoprotein cholesterol and insulin were significantly decreased, and there was an obvious pancreatic injury and inflammatory response in the model group. The choline analogue 3,3-dimethyl-1-butanol (DMB) treatment reversed the changes of serum biochemical parameters, alleviated the pancreatic tissue injury, and reduced the levels of inflammatory cytokines. Further studies of toll-like receptor (TLR)/p-glycoprotein 65 (p65) pathway found that the expressions of TLR2, TLR4, and p-p65/p65 in the model group were significantly increased, which was more obvious after Escherichia coli (Migula) Castellani & Chalmers treatment, while activation of the TLR/p65 pathway was inhibited by DMB. The results indicated that TMAO promotes HAP by promoting inflammatory response through TLR/p65 signaling pathway, suggesting that TMAO may be a potential target of HAP.

The unfolded protein response: An emerging therapeutic target for pancreatitis and pancreatic ductal adenocarcinoma

Pancreatitis is a debilitating disease involving inflammation and fibrosis of the exocrine pancreas. Recurrent or chronic forms of pancreatitis are a significant risk factor for pancreatic ductal adenocarcinoma. While genetic factors have been identified for both pathologies, environmental stresses play a large role in their etiology. All cells have adapted mechanisms to handle acute environmental stress that alters energy demands. A common pathway involved in the stress response involves endoplasmic reticulum stress and the unfolded protein response (UPR). While rapidly activated by many external stressors, in the pancreas the UPR plays a fundamental biological role, likely due to the high protein demands in acinar cells. Despite this, increased UPR activity is observed in response to acute injury or following exposure to risk factors associated with pancreatitis and pancreatic cancer. Studies in animal and cell cultures models show the importance of affecting the UPR in the context of both diseases, and inhibitors have been developed for several specific mediators of the UPR. Given the importance of the UPR to normal acinar cell function, efforts to affect the UPR in the context of disease must be able to specifically target pathology vs. physiology. In this review, we highlight the importance of the UPR to normal and pathological conditions of the exocrine pancreas. We discuss recent studies suggesting the UPR may be involved in the initiation and progression of pancreatitis and PDAC, as well as contributing to chemoresistance that occurs in pancreatic cancer. Finally, we discuss the potential of targeting the UPR for treatment.

Ghee Butter from Bovine Colostrum Reduces Inflammation in the Mouse Model of Acute Pancreatitis with Potential Involvement of Free Fatty Acid Receptors

Acute pancreatitis (AP) is an inflammatory disease that causes severe tissue damage. Ghee butter from bovine colostrum (GBBC) is a clarified butter produced by heating milk fat to 40 °C and separating the precipitating protein. As colostrum mainly contains fatty acids (FAs), immunoglobulins, maternal immune cells, and cytokines, we hypothesized that it may exert anti-inflammatory effects. We investigated the effects of GBBC on experimental AP in mice. Two intraperitoneal (ip) injections of L-arginine (8%) were given 1 h apart to generate the AP murine model. After 12 h from the first L-arginine injection, mice were divided into the following experimental groups: AP mice treated with GBBC (oral gavage (po) every 12 h) and non-treated AP mice (po vehicle every 12 h). Control animals received vehicle only. At 72 h, mice were euthanized. Histopathological examination along with myeloperoxidase (MPO) and amylase/lipase activity assays were performed. In a separate set of experiments, FFAR1 and FFAR4 antagonists were used to verify the involvement of respective receptors. Administration of GBBC decreased MPO activity in the pancreas and lungs along with the microscopical severity of AP in mice. Moreover, treatment with GBBC normalized pancreatic enzyme activity. FFAR1 and FFAR4 antagonists tended to reverse the anti-inflammatory effect of GBBC in mouse AP. Our results suggest that GBBC displays anti-inflammatory effects in the mouse model of AP, with the putative involvement of FFARs. This is the first study to show the anti-inflammatory potential of a nutritional supplement derived from GBBC.

Acinar cell clonal expansion in pancreas homeostasis and carcinogenesis

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer deaths worldwide¹. Studies in human tissues and in mouse models have suggested that for many cancers, stem cells sustain early mutations driving tumour development^2,3. For the pancreas, however, mechanisms underlying cellular renewal and initiation of PDAC remain unresolved. Here, using lineage tracing from the endogenous telomerase reverse transcriptase (Tert) locus, we identify a rare TERT-positive subpopulation of pancreatic acinar cells dispersed throughout the exocrine compartment. During homeostasis, these TERT^high acinar cells renew the pancreas by forming expanding clones of acinar cells, whereas randomly marked acinar cells do not form these clones. Specific expression of mutant Kras in TERT^high acinar cells accelerates acinar clone formation and causes transdifferentiation to ductal pre-invasive pancreatic intraepithelial neoplasms by upregulating Ras-MAPK signalling and activating the downstream kinase ERK (phospho-ERK). In resected human pancreatic neoplasms, we find that foci of phospho-ERK-positive acinar cells are common and frequently contain activating KRAS mutations, suggesting that these acinar regions represent an early cancer precursor lesion. These data support a model in which rare TERT^high acinar cells may sustain KRAS mutations, driving acinar cell expansion and creating a field of aberrant cells initiating pancreatic tumorigenesis.

Untargeted Metabolomics for the Diagnosis of Exocrine Pancreatic Insufficiency in Chronic Pancreatitis

Background and Objectives: The clinical manifestations and course of chronic pancreatitis (CP) are often nonspecific and variable, hampering diagnosis of the risk of exocrine pancreatic insufficiency (EPI). Development of new, reproducible, and non-invasive methods to diagnose EPI is therefore a major priority. The objective of this metabolomic study was to identify novel biomarkers associated with EPI. Materials and Methods: We analyzed 53 samples from patients with CP, 32 with and 21 without EPI, using an untargeted metabolomics workflow based on hydrophilic interaction chromatography coupled to high-resolution mass spectrometry. Principal component and partial least squares-discriminant analyses showed significant between-group differentiation, and univariate and multivariate analyses identified potential candidate metabolites that significantly differed between samples from CP patients with EPI and those without EPI. Results: Excellent results were obtained using a six-metabolic panel to diagnose the presence of EPI in CP patients (area under the ROC curve = 0.785). Conclusions: This study confirms the usefulness of metabolomics in this disease setting, allowing the identification of novel biomarkers to differentiate between the presence and absence of EPI in CP patients.

Chlorogenic acid reduces inflammation in murine model of acute pancreatitis

BACKGROUND

The pathogenesis of acute pancreatitis (AP) initiation and progression is still unknown, and effective treatment is limited to supportive care. Many phytochemicals have the potential to alleviate AP symptoms and may be a useful and effective supplement to standard AP treatment. The objective of the study was to examine the potential role of chlorogenic acid (CGA), a polyphenol known for anti-inflammatory effect, in the treatment of experimental AP in mice.

METHODS

Two intraperitoneal (ip) injections of L-arginine (dosage 400 mg/100 g BW) were given 1 h apart to generate the AP murine model. Mice were separated into two experimental groups after 12 h from the first L-arginine injection: AP mice treated with CGA (oral gavage (po) every 12 h; 20 mg/kg BW) and non-treated AP mice (po vehicle, 5% dimethyl sulfoxide every 12 h). Every 12 h, control mice were given an equivalent volume of vehicle. At 72 h, mice were slaughtered. Histology, as well as myeloperoxidase (MPO) and amylase activity assays, were performed on pancreatic tissues.

RESULTS

In murine mouse model of AP po administration of CGA decreased MPO vs. AP (40.40 ± 2.10 U vs. 7.39 ± 0.34; p < 0.001) as well as amylase activity vs. AP (1444 ± 56 mU/mL vs. 3340 ± 144 mU/mL, Fig. 2B; p < 0.001). When comparing CGA mice to AP mice, histological research demonstrated that the severity of AP was reduced following CGA treatment.

CONCLUSIONS

The current study found that CGA might have anti-inflammatory effect on L-arginine-induced pancreatitis. Dietary intervention with CGA may be advised as a supportive treatment for AP, according to our findings.

Targeting HMGB1/TLR4/NF-κB signaling pathway by protocatechuic acid protects against l-arginine induced acute pancreatitis and multiple organs injury in rats

Acute pancreatitis (AP) is a common pancreatic inflammation associated with substantial morbidity and mortality. AP may be mild or severe which can spread systemically causing multiple organs failure (MOF) and even death. In the current study, protocatechuic acid (PCA), a natural phenolic acid, was investigated for its possible protective potential against L-arginine induced AP and multiple organs injury (MOI) in rats. AP was induced by L-arginine (500 mg/100 g, ip). Two dose levels of PCA were tested (50 and 100 mg/kg, oral, 10 days before L-arginine injection). PCA successfully protected against L-arginine induced AP and MOI that was manifested by normalizing pancreatic, hepatic, pulmonary, and renal tissue architecture and restoring the normal values of pancreatic enzymes (amylase and lipase), serum total protein, liver enzymes (alanine transaminase (ALT) and aspartate transaminase (AST)) and kidney function biomarkers (blood urea nitrogen (BUN) and serum creatinine (Cr)) that were significantly elevated upon L-arginine administration. Additionally, PCA restored balanced oxidant/antioxidants status that was disrupted by L-arginine and normalized pancreatic levels of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) content. Moreover, PCA significantly decreased L-arginine induced elevation in pancreatic high motility group box protein 1 (HMGB1), toll like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nuclear factor kappa B (NF-κB), tumor necrosis factor- α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) expression. PCA significantly ameliorated L-arginine-induced AP and MOI through its anti-inflammatory and antioxidant effects. HMGB1/TLR4/NF-κB was the major pathway involved in the observed protective potential.

Granny Smith Apple Extract Lowers Inflammation and Improves Antioxidant Status in L-arginine-induced Exocrine Pancreatic Dysfunction in Rats

Objectives

Granny Smith is a cultivated hybrid variety of apple with a high antioxidant content relative to all other species of apple. Acute pancreatitis (AP) is an instantly emerging inflammatory condition with a high mortality rate. The preferred treatment is restricted to symptomatic relief and supportive care. The present study was undertaken to evaluate the favorable effects of Granny Smith apple extract (GSAE) as a prophylactic treatment for L-arginine-induced AP in rats.

Materials and Methods

Male Sprague Dawley rats were divided in to five groups (n=6): Normal control (saline), disease control (a single dose of L-arginine 2.5 g/kg I.P.), positive control (pelatonin 10 mg/kg I.P.), and GSAE I and II (200 mg/kg and 400 mg/kg, orally, respectively). All groups were treated for 7 days. At the end of the study, blood samples were collected from the retro-orbital plexus, serum separated, and subjected to estimation of biomarker enzymes such as amylase, lipase, antioxidant enzymes, etc. The animals were then sacrificed, and the pancreas was isolated and subjected to estimation of tissue biomarkers, DNA fragmentation assay, and histopathological studies.

Results

Serum levels of amylase and lipase were significantly (p<0.001) reduced in L-arginine-treated rats. Similar results were also observed with tissue inflammatory markers such as malondialdehyde, nitrate, etc. There was a dramatic increase (p<0.001) in the overall antioxidant enzyme levels when compared with disease control rats. Histopathological examination of pancreatic tissue showed an intact structural feature of acinar cells in the extract-treated group of rats, which was further in pact with the intact DNA found in the DNA fragmentation assay.

Conclusion

Thus, GSAE treatment was found to be beneficial in lowering the inflammatory conditions of AP by improving the overall antioxidant levels, and a further investigation into its exact molecular mechanism is needed.

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

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

Effects of curcumin on oxidative stress, inflammation and apoptosis in L-arginine induced acute pancreatitis in mice

Background and purpose

Curcumin, an active constituent of rhizomes of Curcuma longa Linn, exhibits a variety of biological activities such as anti-inflammation and anti-oxidant. The present study aims to examine the effects of curcumin on oxidative stress, inflammation and apoptosis in L-arginine induced acute pancreatitis (AP) in mice.

Methods

Male ICR mice were randomly divided into 4 groups. Control group received intraperitoneal injection (i.p.) of 1% DMSO as a vehicle. AP group received two doses of i.p. L-arginine (L-Arg) 450 mg/100 g body weight (BW) at 1-hour interval. AP plus low-dose curcumin group received i.p. curcumin 50 mg/kg BW 1 hour before L-Arg injection and then once daily for 3 days. AP plus high-dose curcumin group received i.p. curcumin 200 mg/kg BW 1 hour before L-Arg injection and then once daily for 3 days. All mice were sacrificed at 72 hours. Pancreatic tissue was obtained for histological evaluation, immunohistochemical studies for nuclear factor-kappa beta (NF-kβ), apoptosis and myeloperoxidase (MPO), and Western blot analyses for 4-Hydroxynonenal (4-HNE). Blood samples were collected for amylase analysis.

Results

Mean body weight was significantly lower in AP group than in control group, while in curcumin group, body weight was maintained. The serum amylase, number of MPO positive cells, NF-kB positive cells, TUNEL positive cells, and 4-HNE expression significantly increased in AP group when compared with control group, but decreased in low and high-dose curcumin groups. Mice in AP group developed severe pancreatic inflammation, edema and fat necrosis. While mice in low and high-dose curcumin groups showed a significant improvement in histopathological scores. There was no significant difference between low and high doses of curcumin.

Conclusion

Curcumin could attenuate acute pancreatitis via anti-oxidant, anti-inflammation and anti-apoptosis property leading to the improvement in pancreatic damage.

Evaluation of the Relative Performance of Pancreas-Specific MicroRNAs in Rat Plasma as Biomarkers of Pancreas Injury

Drug-induced pancreatic injury (DIPI) has become linked in recent years to many commonly prescribed medications from several pharmacological classes. Diagnosis is currently most often focused on identification of acute pancreatitis and generally based on subjective clinical assessment and serum amylase and lipase enzymatic activity, which have been criticized as being insufficiently sensitive and specific. The lack of novel noninvasive biomarkers of DIPI can impede the advancement of drug candidates through nonclinical development and translation into clinical settings. Pancreas-specific microRNAs (miRNAs) are currently being evaluated as biomarkers of DIPI that may outperform and/or add value to the interpretation of amylase and lipase. To assess the relative performance of these novel miRNAs, a comprehensive evaluation was conducted to determine the sensitivity and specificity of detecting DIPI in rats. Four miRNAs were evaluated (miR-216a-5p, miR-216b-5p, miR-217-5p, and miR-375-3p) in plasma from 10 studies in which rats were treated with known pancreatic toxicants to assess sensitivity, and from 10 different studies in which toxicity was evident in tissues other than pancreas to assess specificity. The candidate miRNA biomarker performance was compared with amylase and lipase, and receiver operator characteristics (ROC) were determined. Analysis of ROCs demonstrated that all four miRNAs outperformed amylase and lipase in monitoring acute pancreatic injury defined as acinar cell degeneration/necrosis. Specifically, miR-217-5p had the highest performance among all biomarkers assessed. The increased sensitivity and specificity of these miRNAs support their use as biomarkers of DIPI, thereby adding value to the interpretation of amylase and lipase measurements in nonclinical studies. The potential for miRNAs to serve as translational biomarkers in the clinic for the monitoring of DIPI is also supported by this investigation.

Animal Models: Challenges and Opportunities to Determine Optimal Experimental Models of Pancreatitis and Pancreatic Cancer

At the 2018 PancreasFest meeting, experts participating in basic research met to discuss the plethora of available animal models for studying exocrine pancreatic disease. In particular, the discussion focused on the challenges currently facing the field and potential solutions. That meeting culminated in this review, which describes the advantages and limitations of both common and infrequently used models of exocrine pancreatic disease, namely, pancreatitis and exocrine pancreatic cancer. The objective is to provide a comprehensive description of the available models but also to provide investigators with guidance in the application of these models to investigate both environmental and genetic contributions to exocrine pancreatic disease. The content covers both nongenic and genetically engineered models across multiple species (large and small). Recommendations for choosing the appropriate model as well as how to conduct and present results are provided.

Bidirectional Effects of Pyrrolidine Dithiocarbamate on Severe Acute Pancreatitis in a Rat Model

Introduction

The mechanism by which intestinal mucosal barrier is damaged in severe acute pancreatitis (SAP)-associated impairment is not fully understood.

Methods

We established an l-arginine-induced SAP rat model, pretreated with or without pyrrolidine dithiocarbamate (PDTC). Hematoxylin and eosin staining was performed to evaluate the pathological alterations. Western blotting was conducted to detect the expression of autophagy-related proteins. Oxidative stress was assessed by the levels of malondialdehyde and superoxide dismutase.

Results

We found significant injury of the intestinal mucosal barrier in SAP rats, with overexpression of Beclin-1, LC3, and p65. Pyrrolidine dithiocarbamate showed a bidirectional effect in protecting SAP rats. A high dose of PDTC aggravated disease in rats, while a low or medium dose of PDTC pretreatment, was able to alleviate tissue damage. Pyrrolidine dithiocarbamate changed the expression of Beclin-1, LC3, and p65 in the intestines. The fatty acid-binding protein level was increased in SAP rats with high-dose PDTC or without PDTC pretreatment and was reduced in SAP rats with low- or medium-dose PDTC exposure.

Conclusions

Autophagy is involved in the impairment of intestinal mucosal barrier during SAP. A suitable dose of PDTC (1 or 10 mg/kg) may decrease the severity of SAP by inhibiting autophagy in intestinal mucosal cells.

An Intestinal "Transformers"-like Nanocarrier System for Enhancing the Oral Bioavailability of Poorly Water-Soluble Drugs

Increasing the intestinal dissolution of orally administered poorly water-soluble drugs that have poor oral bioavailability to a therapeutically effective level has long been an elusive goal. In this work, an approach that can greatly enhance the oral bioavailability of a poorly water-soluble drug such as curcumin (CUR) is developed, using a "Transformers"-like nanocarrier system (TLNS) that can self-emulsify the drug molecules in the intestinal lumen to form nanoemulsions. Owing to its known anti-inflammation activity, the use of CUR in treating pancreatitis is evaluated herein. Structural changes of the TLNS in the intestinal environment to form the CUR-laden nanoemulsions are confirmed in vitro. The therapeutic efficacy of this TLNS is evaluated in rats with experimentally induced acute pancreatitis (AP). Notably, the CUR-laden nanoemulsions that are obtained using the proposed TLNS can passively target intestinal M cells, in which they are transcytosed and then transported into the pancreatic tissues via the intestinal lymphatic system. The pancreases in rats that are treated with the TLNS yield approximately 12 times stronger CUR signals than their counterparts receiving free CUR, potentially improving the recovery of AP. These findings demonstrate that the proposed TLNS can markedly increase the intestinal drug dissolution, making oral delivery a favorable noninvasive means of administering poorly water-soluble drugs.

Genetically induced vs. classical animal models of chronic pancreatitis: a critical comparison

Chronic pancreatitis (CP) is an utmost complex disease that is pathogenetically linked to pancreas-intrinsic ( e.g., duct obstruction), environmental-toxic ( e.g., alcohol, smoking), and genetic factors. Studying such a complex disease naturally requires validated experimental models. In the past 2 decades, the various animal models of CP usually addressed either the pancreas-intrinsic ( e.g., the caerulein model), the environmental-toxic ( e.g., diet-induced models), or the genetic component of CP. As such, these models were far from mirroring CP in its full spectrum, and the correct choice of models was vital for valid scientific conclusions on CP. The quest for mechanistic, genetic models gave rise to models based on gene modification and transgene insertion, such as the PRSS1 and the IL-1β/IL-1β models. Recently, we witnessed the development of highly exciting models that rely on the importance of autophagy in CP, that is, the murine pancreas-specific Atg5 and LAMP2 knockout models. Today, critical comparison of these several models is more important than ever for guiding research on CP in an efficient direction. The present review outlines the characteristics of the new genetic models in comparison with the well-known classic models for CP, notes the caveats in the choice of models, and also indicates novel directions for model development.-Klauss, S., Schorn, S., Teller, S., Steenfadt, H., Friess, H., Ceyhan, G. O., Demir, I. K. Genetically induced vs. classical animal models of chronic pancreatitis: a critical comparison.

The second case of a young man with L-arginine-induced acute pancreatitis

BACKGROUND

Dietary supplementation of arginine has been used by numerous world-class athletes and professional bodybuilders over the past 30 years. L-Arginine indeed enhances muscular power and general performance via maintaining ATP level. However, L-arginine is also known to induce acute pancreatitis in murine models.

CASE REPORT

We report the case of young man presenting with upper abdominal pain and increased serum lipase levels. Contrast-enhanced computed tomography confirms a mild acute pancreatitis. Common etiologies have been ruled out and toxicological anamnestic screening reveals the intake of protein powder. This is, to the best of our knowledge, the second case in human of arginine-induced acute pancreatitis.

CONCLUSION

This case report suggests that every patient presenting with acute pancreatitis without obvious etiology should be evaluated for the intake of toxics other than alcohol, including L-arginine.

Accelerating the Drug Delivery Pipeline for Acute and Chronic Pancreatitis-Knowledge Gaps and Research Opportunities: Overview Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop

A workshop was sponsored by the Division of Digestive Diseases and Nutrition, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, on July 25, 2018, in Pittsburgh, Penn. The workshop was designed to bring together a multidisciplinary group of experts to accelerate the development of therapeutics for clinical application in inflammatory diseases of the exocrine pancreas. Three separate working groups (acute pancreatitis, recurrent acute pancreatitis, and chronic pancreatitis) were formed to address the needs, gaps, and opportunities. The working groups included patients with pancreatic diseases, pharmaceutical company leaders, basic scientists, clinical researchers, and representatives from the US Food and Drug Administration to assist with regulatory considerations and to identify the unmet needs, research targets, and opportunities to provide direction for successful development of therapeutic agents in these diseases. This article represents the summary of the overview presentations at the National Institute of Diabetes and Digestive and Kidney Diseases workshop including an ongoing drug trial in acute pancreatitis; a successful drug development network developed by the Cystic Fibrosis Foundation; and considerations for subject selection in drug trials, incorporating Food and Drug Administration guidelines on clinical trial design and clinical outcome measures. The summaries of each working group follow separately in accompanying articles.

Accelerating the Drug Delivery Pipeline for Acute and Chronic Pancreatitis: Summary of the Working Group on Drug Development and Trials in Acute Pancreatitis at the National Institute of Diabetes and Digestive and Kidney Diseases Workshop

A workshop was sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases to focus on research gaps and opportunities on drug development for pancreatitis. This conference was held on July 25, 2018, and structured into 3 working groups (WG): acute pancreatitis (AP) WG, recurrent AP WG, and chronic pancreatitis WG. This article reports the outcome of the work accomplished by the AP WG to provide the natural history, epidemiology, and current management of AP; inform about the role of preclinical models in therapy selection; and discuss clinical trial designs with clinical and patient-reported outcomes to test new therapies.

Chai-Qin-Cheng-Qi Decoction and Carbachol Improve Intestinal Motility by Regulating Protein Kinase C-Mediated Ca2+ Release in Colonic Smooth Muscle Cells in Rats with Acute Necrotising Pancreatitis

Chai-Qin-Cheng-Qi decoction (CQCQD) improves intestinal motility in acute pancreatitis (AP), but the mechanism(s) require elucidation. We investigated the effects of CQCQD and carbachol, a prokinetic agent, on colonic smooth muscle cells (SMCs) in L-arginine-induced necrotising AP model in rats. In treatment groups, intragastric CQCQD (20 g/kg, 2 hourly × 3 doses) or intraperitoneal carbachol (60 μg/kg) was given 24 hours after induction of AP. Both CQCQD and carbachol decreased the severity of pancreatic and colonic histopathology (all P < 0.05). Both CQCQD and carbachol reduced serum intestinal fatty acid binding protein, vasoactive intestinal peptide, and substance P and increased motility levels. CQCQD upregulated SMC phospholipase C-beta 1 (PLC-β1) mRNA and PLC protein (both P < 0.05), while both treatments upregulated protein kinase C-alpha (PKC-α) mRNA and PKC protein and downregulated adenylate cyclase (AC) mRNA and protein compared with no treatment (all P < 0.05). Neither treatment significantly altered L-arginine-induced PKC-β1 and PKC-ε mRNA reduction. Both treatments significantly increased fluorescence intensity of SMC intracellular calcium concentration [Ca²⁺]_i (3563.5 and 3046.9 versus 1086.9, both P < 0.01). These data suggest CQCQD and carbachol improve intestinal motility in AP by increasing [Ca²⁺]_i in colonic SMCs via upregulating PLC, PKC and downregulating AC.

Morphological and immunobiochemical analysis of the liver in L-arginine induced experimental chronic pancreatitis

BACKGROUND

Clinical evidence indicates that hepatic abnormalities in patients with chronic pancreatitis are not uncommon. Here we aimed to study the possible association between liver and pancreatic damage in a recently described experimental mouse model of CP.

METHODS

The severity of the damage to pancreas, liver and other organs was assessed by biochemical markers and histopathology. The methods applied included Hematoxylin Eosin staining, electron microscope examination, biochemical measurements, RT-PCR, ELISA, and the correlations among some of the parameters contributing to these changes were statistically analyzed.

RESULTS

The hepatic aberrations were mainly represented by mild infiltration of inflammatory cells in portal triad and congestion of central vein of liver, and the main features of drug-induced hepatotoxicity could not be observed. Severe fibrosis of pancreatic tissue was noticed in experimental group, and the existence of multiple organ injuries was also seen under the microscope. Hepatic pathologic scores were positively correlated with those from the corresponding pancreatic specimens (r = 0.72, P < 0.01). TGF-β1 protein levels significantly elevated both in the test pancreas and liver (P < 0.05) and these values were positively correlated (r = 0.86, P < 0.01). The level of interleukin-1β was increased in the serum and tissue of the liver. In addition, cardiac troponin (Tn-I) level not only significantly increased in myocardial homogenates (P < 0.05) but also was positively correlated with the corresponding pathologic score of the liver (r = 0.88, P < 0.01).

CONCLUSION

The liver aberrations might be associated with L-arginine induced chronic pancreatitis.

Calendula officinalis ameliorates l-arginine-induced acute necrotizing pancreatitis in rats

CONTEXT

Calendula officinalis L. (Asteraceae) has been traditionally used in treating inflammation of internal organs, gastrointestinal tract ulcers and wound healing.

OBJECTIVE

The present study investigates the effect of ethanol extract (95%) of Calendula officinalis flowers in l-arginine induced acute necrotizing pancreatitis in rats.

MATERIALS AND METHODS

Rats were divided into four groups: normal control, l-arginine control, Calendula officinalis extract (COE) treated and melatonin treated (positive control), which were further divided into subgroups (24 h, day 3 and 14) according to time points. Two injections of l-arginine 2 g/kg i.p. at 1 h intervals were administered in l-arginine control, COE and melatonin-treated groups to produce acute necrotizing pancreatitis. Biochemical parameters [serum amylase, lipase, pancreatic amylase, nucleic acid content, total proteins, transforming growth factor-β1 (TGF-β1), collagen content, lipid peroxidation, reduced glutathione and nitrite/nitrate] and histopathological studies were carried out.

RESULTS

COE treatment (400 mg/kg p.o.) was found to be beneficial. This was evidenced by significantly lowered histopathological scores (2 at day 14). Nucleic acid content (DNA 21.1 and RNA 5.44 mg/g pancreas), total proteins (0.66 mg/mL pancreas) and pancreatic amylase (1031.3 100 SU/g pancreas) were significantly improved. Marked reduction in pancreatic oxidative and nitrosative stress; collagen (122 μmoles/100 mg pancreas) and TGF-β1 (118.56 pg/mL) levels were noted. Results obtained were comparable to those of positive control.

DISCUSSION AND CONCLUSION

The beneficial effect of COE may be attributed to its antioxidant, antinitrosative and antifibrotic actions. Hence, the study concludes that COE promotes spontaneous repair and regeneration of the pancreas.

Prophylactic Administration of Silybin Ameliorates L-Arginine-Induced Acute Pancreatitis

Background

Oxidative stress have been shown to play a role in the pathogenesis of acute pancreatitis. The aim of this study was to investigate the potential effect of silybin, a potent antioxidant, on L-arginine-induced acute pancreatitis in an experimental rat model.

Material/Methods

Forty female Wistar Albino rats were divided into 5 groups as follows: Group 1 (C): control group (n=8), Group 2 (SL): silybin group (n=8), Group 3 (LA): acute pancreatitis group (n=8), Group 4 (SLLA): prophylaxis group (n=8), and Group 5 (LASL): treatment group (n=8). Group C (control) received 2 intraperitoneal (i.p.) injections of physiological saline at an interval of 1 h. Group SL received only a single i.p. injection of silybin. The SLLA group received a single i.p. injection of silybin before the induction of acute pancreatitis with L-arginine, whereas the LASL group received the same injection after the induction of acute pancreatitis with L-arginine. Pancreatic tissues were histopathologically examined. Levels of amylase and oxidative stress markers (total oxidant status and total anti-oxidant status) were determined in the blood samples. Oxidative stress index was calculated.

Results

In comparison to the LA, the prophylaxis and treatment groups showed significant improvements in serum oxidative stress parameters (p=0.001 and p=0.005, respectively). Histopathological analysis showed that the treatment group had significant improvements in edema scores only (p=0.006), whereas the prophylaxis group had the same improvements in inflammation and necrosis scores as well as in total scores (p=0.004, 0.006, and 0.004, respectively).

Conclusions

When used for prophylactic rather than therapeutic purposes, silybin ameliorates serum oxidative stress parameters and improves histopathological results via its antioxidant and anti-inflammatory properties.

Experimental Models in Syrian Golden Hamster Replicate Human Acute Pancreatitis

The hamster has been shown to share a variety of metabolic similarities with humans. To replicate human acute pancreatitis with hamsters, we comparatively studied the efficacy of common methods, such as the peritoneal injections of caerulein, L-arginine, the retrograde infusion of sodium taurocholate, and another novel model with concomitant administration of ethanol and fatty acid. The severity of pancreatitis was evaluated by serum amylase activity, pathological scores, myeloperoxidase activity, and the expression of inflammation factors in pancreas. The results support that the severity of pathological injury is consistent with the pancreatitis induced in mice and rat using the same methods. Specifically, caerulein induced mild edematous pancreatitis accompanied by minimal lung injury, while L-arginine induced extremely severe pancreatic injury including necrosis and neutrophil infiltration. Infusion of Na-taurocholate into the pancreatic duct induced necrotizing pancreatitis in the head of pancreas and lighter inflammation in the distal region. The severity of acute pancreatitis induced by combination of ethanol and fatty acids was between the extent of caerulein and L-arginine induction, with obvious inflammatory cells infiltration. In view of the advantages in lipid metabolism features, hamster models are ideally suited for the studies of pancreatitis associated with altered metabolism in humans.

Tissue-specific regulation of potassium homeostasis by high doses of cationic amino acids

The administration of l-arginine hydrochloride has been used for testing pituitary secretion in humans, and as an experimental model for induction of acute pancreatitis in rats and mice. Whereas in the first case, the administration of the amino acid is associated with hiperkalemia, in the model of acute pancreatitis no data are available on possible changes in potassium homeostasis. The present study shows that the acute administration to mice of l-arginine hydrochloride or other cationic amino acids almost duplicate plasma potassium levels. This effect was associated to a marked decrease of tissue potassium in both pancreas and liver. No changes were found in other tissues. These changes cannot be ascribed to the large load of chloride ions, since similar effects were produced when l-ornithine aspartate was administered. The changes in potassium levels were dependent on the dose. The displacement of intracellular potassium from the liver and pancreas to the extracellular compartment appears to be dependent on the entry of the cationic amino acid, since the administration of an equivalent dose of alfa-difluoromethyl ornithine HCl (DFMO), a non physiological analog of l-ornithine, which is poorly taken by the tissues in comparison with the physiological cationic amino acids, did not produce any change in potassium levels in pancreas and liver. The analyses of the expression of cationic amino acid transporters (CAT) suggest that the CAT-2 transporter may be implicated in the potassium/cationic amino acid interchange in liver and pancreas. The possible physiological or pathological relevance of these findings is discussed.

A new experimental rat model of pancreatitis using Ecballium elaterium

BACKGROUND

We originally aimed to determine the beneficial effects of Ecballium Elaterium (EE) on acute pancreatitis; however, we observed negative effects of EE on the pancreas. Thus, we used EE in rats to generate a new model of pancreatitis, which we compared with other established pancreatitis models.

METHODS

A total of 32 Wistar albino rats were used. Rats were divided into 4 groups, each of which contained 8 rats. Group 1 (Control), Group 2 (L-Arginine (LA), Group 3 (LA + EE), Group 4 (EE): Twenty-four hours after that serum parameters were analyzed in the collected blood. Blood samples were transported on mice to the Biochemistry Laboratory following cardiac puncture. The levels of amylase, interleukin (IL)-6, interleukin (IL) 1-β (IL-1β), malondialdhyde (MDA), tumor necrosis factor (TNF)-α, total antioxidant status (TAS), and total oxidant status (TOS) were analyzed. Histopathological analysis: The pancreas and lung tissue samples obtained from the rats. Edema, inflammation, vacuolization, and necrosis of the pancreas were assessed using a scoring system ranging from 0 to 4. Edema, hemorrhage and inflammation of the lung tissue were evaluated using a scoring system ranging from 0 to 3.

RESULTS

Histopathological analysis revealed that edema, inflammation, necrosis, and hemorrhage were significantly higher in the LA + EE group than in the control group. Moreover, necrosis was higher in the rats that received LA and EE compared to the rats that received only LA or EE. Increases in inflammatory mediator levels, including IL-6, IL-1β, TNF-α, MDA, and TOS, were observed in all groups as compared to the control group. Moreover, lower TAS levels were detected in all groups but the control group. The increase in IL-1β and TNF-α levels and the decrease in TAS were statistically significant in all groups (P < 0.05).

CONCLUSIONS

EE may be used to create a successful acute pancreatitis (AP) model, resulting in edema, necrosis, hemorrhage, and inflammation of the pancreas. The major advantage of this model is that it does not require laparotomy, and can be implemented with only an intraperitoneal injection (IP). Moreover, EE may be combined with other agents, such as LA, to create severe pancreatitis. Further molecular studies are warranted to determine the underlying effects of EE on the pancreas.

Suppression of acute pancreatitis by L-lysine in mice

BACKGROUND

Acute pancreatitis is an inflammatory disease caused by several factors such as viral infection, drugs, and diagnostic endoscopy. The aim of this study was to evaluate the potential protective or therapeutic effects of L-lysine on pancreatitis induced by L-arginine in mice.

METHODS

Four groups of mice (10 in each group) were assessed. Group I was the control. Animals in groups II-IV were injected intraperitoneally with L-arginine hydrochloride (400 mg/kg body weight [bw]) for 3 days. Group III animals were orally pre-treated with L-lysine (10 mg/kg bw), whereas group IV animals were orally post-treated with L-lysine (10 mg/kg bw). Serum samples were subjected to amylase, lipase, transaminase, and interleukin-6 (IL-6) assays. The pancreas was excised to measure the levels of malondialdehyde, nitric oxide, catalase, superoxide dismutase, reduced glutathione, and glutathione peroxidase.

RESULTS

Pre- or post-treatment with L-lysine led to significant decreases in the levels of malondialdehyde and nitric oxide, while significant enhancement was observed in the activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and glutathione (p < 0.001). However, the treatment potential of L-lysine was better as a protective agent than a therapeutic agent.

CONCLUSIONS

L-lysine treatment attenuates pancreatic tissue injury induced by L-arginine by inhibiting the release of the inflammatory cytokine IL-6 and enhance antioxidant activity. These effects may involve upregulation of anti-inflammatory factors and subsequent downregulation of IL6.

Evolving paradigm of illnesses presented to medical Intensive Care Unit in body builders: Cases from tertiary care center

Bodybuilding is the use of progressive resistance exercise to control and develop one's musculature. With the rise in number of persons adopting this activity, there is evolving paradigm of illnesses presented to intensive care in this population subset. Strict adherence to details of bodybuilding and avoidance of unsupervised medications are essential to prevent untoward effects.

New insights into the methodology of L-arginine-induced acute pancreatitis

Animal models are ideal to study the pathomechanism and therapy of acute pancreatitis (AP). The use of L-arginine-induced AP model is nowadays becoming increasingly popular in mice. However, carefully looking through the literature, marked differences in disease severity could be observed. In fact, while setting up the L-arginine (2×4 g/kg i.p.)-induced AP model in BALB/c mice, we found a relatively low rate (around 15%) of pancreatic necrosis, whereas others have detected much higher rates (up to 55%). We suspected that this may be due to differences between mouse strains. We administered various concentrations (5–30%, pH = 7.4) and doses (2×4, 3×3, or 4×2.5 g/kg) of L-arginine-HCl in BALB/c, FVB/n and C57BL/6 mice. The potential gender-specific effect of L-arginine was investigated in C57BL/6 mice. The fate of mice in response to the i.p. injections of L arginine followed one of three courses. Some mice (1) developed severe AP or (2) remained AP-free by 72 h, whereas others (3) had to be euthanized (to avoid their death, which was caused by the high dose of L-arginine and not AP) within 12 h., In FVB/n and C57BL/6 mice, the pancreatic necrosis rate (about 50%) was significantly higher than that observed in BALB/c mice using 2×4 g/kg 10% L–arginine, but euthanasia was necessary in a large proportion of animals, The i.p. injection of lower L-arginine concentrations (e.g. 5–8%) in case of the 2×4 g/kg dose, or other L-arginine doses (3×3 or 4×2.5 g/kg, 10%) were better for inducing AP. We could not detect any significant differences between the AP severity of male and female mice. Taken together, when setting up the L-arginine-induced AP model, there are several important factors that are worth consideration such as the dose and concentration of the administered L arginine-HCl solution and also the strain of mice.

[COMPOSITION OF GASTRIC JUICE AND BILE IN RATS AT THE EXPERIMENTAL CHRONIC PANCREATITIS]

Chronic pancreatitis is an inflammatory disease of the pancreas, which is characterized by destruction of pancreatic secretory parenchyma and progressing exocrine and endocrine insufficiency. Usually these patients have complications as cardiovascular, renal, respiratory and liver failure, and various gastric dysfunctions. The data of clinical observations do not reveal fully the functional state of the stomach and liver in chronic pancreatitis also remains an open question about the quality of the gastric juices and bile by this pathology. Therefore our aim was to investigate the secretory functions of the stomach and liver features in rats at the experimental chronic pancreatitis. This pathology modeled using L-arginine. Basal gastric secretion was investigated in chronic experiment by aspiration method for 10th and 63rd days, and pancreas and liver--in acute experiments at 13th and 68th days after the last administration of L-arginine. It was established that the character of the secretory response of the digestive tract depends on the duration of the pathology course. On the 10th day the functional state of the gastric secretory glands in rats with chronic pancreatitis characterized by twice increase of gastric acid production but decrease the level of hexosamines on 23.8% (P < 0.001) that indicate a increase of gastric content aggressiveness and mucus producing cells secretory insufficiency. In these animals the rate of total protein decreased on 61.7% (P < 0.05). On the 13th day observed the increase of pancreatic juice on 332% (P < 0.01), hepatic secret volume on 74.9% (P < 0.001) and redistribution in the cholates spectrum: glycocholates level increased but tauro-, free and total dehydroxylated bile acids decreased. These changes suggest deterioration of bile detergent properties, inhibition of acidic pathway of bile acids biosynthesis and conjugation of cholates with taurine. In two months total deficit of amino acids in gastric juice correlated with exocrine pancreatic insufficiency. Herein the acidity of gastric content partially restored, while the level of protein and mucus secretion proceed to decline. Consequently gastric mucosa is more vulnerable. In these rats the rates of free bile acids greatly increased while tauro- and glycocholates significantly decreased. Thus the processes of hydroxylation and conjugation of bile acids with amino acids inhibited suggesting interruption of synthetic and detoxification functions of the liver. The present work is important for comprehension the pathophysiological aspects of chronic pancreatitis particularly the digestive system functioning features at this pathology. These data could be considered in the appointment of treatment to avoid complications.

Clinical and pathologic characteristics of pancreatic necrosis in critically ill children

BACKGROUND

Pancreatic damage in critically ill patients is associated with the progressive failure of multiple organs, but little is known about its clinical characteristics. At present, no guidelines are available for the diagnosis and management of pancreatic damage. This study was undertaken to analyze the clinical and pathologic characteristics of pancreatic necrosis in critically ill children, and to find some biological markers of pancreatic damage or pancreatic necrosis.

METHODS

We retrospectively reviewed the clinical data, laboratory results, and autopsy findings of 25 children, who were admitted to Hunan Children's Hospital, China from 2003 to 2009, and died of multiple organ failure. The autopsy revealed pancreatic necrosis in 5 children, in whom sectional or gross autopsy was performed.

RESULTS

The 5 children had acute onset and a fever. Two children had abdominal pain and 2 had abdominal bulging, flatulence and gastrointestinal bleeding. Four children had abnormal liver function, characterized by decreased albumin and 3 children had elevated level of C-reactive protein (CRP). B-ultrasonography revealed abnormal acoustic image of the pancreas in all children, and autopsy confirmed pancreatic necrosis, which may be associated with the damage of the adrenal gland, liver, lung, heart, spleen, kidney, intestine, thymus, mediastinal and mesenteric lymph nodes and other organs. Children 1 and 2 died of acute hemorrhagic necrotizing pancreatitis (AHNP); children 3-5 died of multiple organ dysfunction syndrome (MODS) due to pancreatic necrosis.

CONCLUSION

Pancreatic damage or pancreatic necrosis in critically ill children is characterized by acute onset, severity, short course, multiple organ damage or failure. It may be asymptomatic in early stage, and easy to be ignored.

Insulin protects pancreatic acinar cells from palmitoleic acid-induced cellular injury

Acute pancreatitis is a serious and sometimes fatal inflammatory disease where the pancreas digests itself. The non-oxidative ethanol metabolites palmitoleic acid (POA) and POA-ethylester (POAEE) are reported to induce pancreatitis caused by impaired mitochondrial metabolism, cytosolic Ca²⁺ ([Ca²⁺]_i) overload and necrosis of pancreatic acinar cells. Metabolism and [Ca²⁺]_i are linked critically by the ATP-driven plasma membrane Ca²⁺-ATPase (PMCA) important for maintaining low resting [Ca²⁺]_i. The aim of the current study was to test the protective effects of insulin on cellular injury induced by the pancreatitis-inducing agents, ethanol, POA, and POAEE. Rat pancreatic acinar cells were isolated by collagenase digestion and [Ca²⁺]_i was measured by fura-2 imaging. An in situ [Ca²⁺]_i clearance assay was used to assess PMCA activity. Magnesium green (MgGreen) and a luciferase-based ATP kit were used to assess cellular ATP depletion. Ethanol (100 mm) and POAEE (100 μm) induced a small but irreversible Ca²⁺ overload response but had no significant effect on PMCA activity. POA (50–100 μm) induced a robust Ca²⁺ overload, ATP depletion, inhibited PMCA activity, and consequently induced necrosis. Insulin pretreatment (100 nm for 30 min) prevented the POA-induced Ca²⁺ overload, ATP depletion, inhibition of the PMCA, and necrosis. Moreover, the insulin-mediated protection of the POA-induced Ca²⁺ overload was partially prevented by the phosphoinositide-3-kinase (PI3K) inhibitor, LY294002. These data provide the first evidence that insulin directly protects pancreatic acinar cell injury induced by bona fide pancreatitis-inducing agents, such as POA. This may have important therapeutic implications for the treatment of pancreatitis.

Hypothermia induced by adenosine 5'-monophosphate attenuates injury in an L-arginine-induced acute pancreatitis rat model

BACKGROUND AND AIM

This study sought to investigate the effects of hypothermia induced by adenosine 5'-monophosphate (5'-AMP) on L-arginine (L-Arg)-induced acute pancreatitis in rats.

METHODS

The rats were divided into four groups: the control group, the acute pancreatitis group, the 5'-AMP pretreatment group, and the 5'-AMP posttreatment group. Rats in all groups, except for the control group, received two injections of 2.5 g/kg body weight (intraperitoneally) L-Arg, with an interval of 1 h between the injections. Subsequently, the rats were observed to assess whether hypothermia induced by 5'-AMP could effectively inhibit inflammation associated with L-Arg-induced acute pancreatitis in rats.

RESULTS

Hypothermia induced by 5'-AMP produced protective effects in our acute pancreatitis model. These effects exhibited the following manifestations: (i) a significant reduction in rat mortality rates; (ii) a significant decrease in the occurrence of pancreatic edema; (iii) significant reductions in serum amylase (P < 0.001), interleukin-6 (P < 0.001), interleukin-1β (P < 0.001) and tumor necrosis factor-α (P < 0.001); (iv) the significant inhibition of nuclear factor-κB (NF-κB) activation in rats that were pre- and posttreated with 5'-AMP compared with rats that were only injected with L-Arg; and (v) significant decreases in the occurrence of pancreatic interstitial edema, inflammatory cell infiltration, hemorrhage, and acinar cell necrosis.

CONCLUSIONS

Hypothermia induced by 5'-AMP could inhibit the acute inflammatory reaction and NF-κB activation associated with acute pancreatitis.

Characterization of the exocrine pancreas in the male Zucker diabetic fatty rat model of type 2 diabetes mellitus following 3 months of treatment with sitagliptin

Sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor-based incretin therapy intended for the treatment of type 2 diabetes mellitus (T2DM), has not been linked to adverse effects on the pancreas in prospective clinical trials or in nonclinical toxicology studies. To further assess potential pancreatic effects, sitagliptin was studied in the male Zucker diabetic fatty (ZDF) rat model of T2DM. Following 3 months of oral dosing with vehicle, or sitagliptin at doses 3- to 19-fold above the clinically therapeutic plasma concentration, which increased active plasma glucagon-like peptide-1 levels up to approximately 3-fold, or following 3 months of oral dosing with metformin, a non-incretin-based reference T2DM treatment, the pancreas of male ZDF rats was evaluated using qualitative and quantitative histopathology techniques. In the quantitative evaluation, proliferative index was calculated in exocrine pancreatic ducts and ductules using computer-based image analysis on sections stained by immunohistochemistry for cytokeratin (a cytoplasmic epithelial cell marker) and Ki-67 (a nuclear marker of recent cell division). Relative to controls, sitagliptin treatment did not alter disease progression based on detailed clinical signs and clinical pathology assessments. Sitagliptin treatment did not result in pancreatitis or any adverse effect on the pancreas based on a qualitative histopathology evaluation. Proliferative index did not increase with sitagliptin treatment based on quantitative assessment of more than 5000 sections of pancreas, where control group means ranged from 0.698-0.845% and sitagliptin-treated group means ranged from 0.679-0.701% (P = .874). Metformin treatment was similarly evaluated and found not to have adverse effects on pancreas.

Recent advances in the investigation of pancreatic inflammation induced by large doses of basic amino acids in rodents

It has been known for approximately 30 years that large doses of the semi-essential basic amino acid L-arginine induce severe pancreatic inflammation in rats. Recently, it has been demonstrated that L-arginine can also induce pancreatitis in mice. Moreover, other basic amino acids like L-ornithine and L-lysine can cause exocrine pancreatic damage without affecting the endocrine parenchyma and the ducts in rats. The utilization of these noninvasive severe basic amino acid-induced pancreatitis models is becoming increasingly popular and appreciated as these models nicely reproduce most laboratory and morphological features of human pancreatitis. Consequently, the investigation of basic amino acid-induced pancreatitis may offer us a better understanding of the pathogenesis and possible treatment options of the human disease.

Antioxidant activity of simvastatin prevents L-arginine-induced acute toxicity of pancreas

L-arginine is a semi-essential amino acid that found naturally in food. It has been shown that administration of large doses of L-arginine can induce acute pancreatitis. In the present study, we evaluated if simvastatin, a 3-hydroxy-methylglutaryl coenzyme A reductase (HMG-CoA reductase) inhibitor, might prevent acute pancreatitis induced by L-arginine. Thirty male Wistar rats were randomly allocated to five groups. Groups were: DMSO, saline, simvastatin, L-arginine, and simvastatin with L-arginine. Twenty four hours after the last dose, rats were sacrificed and their blood was collected from heart for biochemical analysis. Pancreatic tissues were obtained for analysis of glutathione peroxidase (GPx), glutathione s-transferase (GST), lipid peroxide levels (MDA) and histology analysis was examined for pancreas. Results indicated that treatment with simvastatin significantly enhanced levels of GPx and GST and decreased lipid peroxide levels induced by L-arginine compared to the vehicle. Moreover, histopathological analysis further confirmed that administration of simvastatin relatively prevented pancreatic acinar cell damage compared to those animals received L-arginine alone. These findings pointed out the protective role of simvastatin against acute pancreatitis induced by high doses of L-arginine.

Oxymatrine ameliorates L-arginine-induced acute pancreatitis in rats

The aim of this study was to determine whether oxymatrine has a protective effect against acute pancreatitis (AP) in a rat model of L-arginine-induced AP. AP was induced by two intraperitoneal injections of L-arginine (250 mg/100 g) at a 1-h interval. Oxymatrine (50 mg/kg) was administered every 6 h after the induction of AP. Oxymatrine significantly reduced the plasma amylase, D-lactic acid and tumor necrosis factor alpha concentration, serum diamine oxidase and lipase activity, and pancreatic myeloperoxidase activity, which were increased in AP rats (P < 0.05). In addition, the pancreatic CD45 expression and the expression of claudin-1, but not zonula occludens-1 (ZO-1) and occludin, in the intestinal tissues were significantly reduced after the induction of AP. However, oxymatrine increased the expression of claudin-1 and CD45, but did not alter the expression of ZO-1 and occludin. In conclusion, our results demonstrated that oxymatrine is potentially capably of protecting against L-arginine-induced AP and attenuating AP-associated intestinal barrier injury by up-regulation of claudin-1.

Pathophysiology of acute pancreatitis: potential application from experimental models and human medicine to dogs

The cellular events leading to pancreatitis have been studied extensively in experimental models. Understanding the cellular events and inciting causes of the multisystem inflammatory cascades that are activated with this disease is of vital importance to advance diagnosis and treatment of this condition. Unfortunately, the pathophysiology of pancreatitis in dogs is not well understood, and extrapolation from experimental and human medicine is necessary. The interplay of the inflammatory cascades (kinin, complement, cytokine) is extremely complex in both initiating leukocyte migration and perpetuating disease. Recently, nitric oxide (NO) and altered microcirculation of the pancreas have been proposed as major initiators of inflammation. In addition, the role of the gut is becoming increasingly explored as a cause of oxidative stress and potentiation of systemic inflammation in pancreatitis.