Experimental Model Of Chronic Pancreatitis Research Articles

Inhibition of discoidin domain receptors by imatinib prevented pancreatic fibrosis demonstrated in experimental chronic pancreatitis model

Discoidin domain receptors (DDR1 and DDR2) are the collagen receptors of the family tyrosine kinases, which play significant role in the diseases like inflammation, fibrosis and cancer. Chronic pancreatitis (CP) is a fibro-inflammatory disease in which recurrent pancreatic inflammation leads to pancreatic fibrosis. In the present study, we have investigated the role of DDR1 and DDR2 in CP. The induced expression of DDR1 and DDR2 was observed in primary pancreatic stellate cells (PSCs) and cerulein-induced CP. Subsequently, the protective effects of DDR1/DDR2 inhibitor, imatinib (IMT) were investigated. Pharmacological intervention with IMT effectively downregulated DDR1 and DDR2 expression. Further, IMT treatment reduced pancreatic injury, inflammation, extracellular matrix deposition and PSCs activation along with inhibition of TGF-β1/Smad signaling pathway. Taken together, these results suggest that inhibition of DDR1 and DDR2 controls pancreatic inflammation and fibrosis, which could represent an attractive and promising therapeutic strategy for the treatment of CP.

Pentoxifylline has favorable preventive effects on experimental chronic pancreatitis model

Background: To investigate the protective efficacy of pentoxifylline through biochemical parameters and histopathological scores in a caerulein- and alcohol-induced experimental model of chronic pancreatitis in rats.Methods: A model of chronic pancreatitis with caerulein and alcohol was created in female rats of the genus Sprague Dawley. Pentoxifylline was administered in doses of 25 mg/kg (low dose) and 50 mg/kg (high dose) as a protective agent. Each group contained 8 animals. The groups were: group 1 (control group); caerulein + alcohol, group 2 (low-dose pentoxifylline group); caerulein + alcohol + pentoxifylline 25 mg/kg, group 3 (high-dose pentoxifylline group); caerulein + alcohol + pentoxifylline 50 mg/kg, group 4 (placebo); caerulein + alcohol + saline, group 5 (sham group); only saline injection.Rats were sacrificed 12 h after the last injection, and TNF-α, TGF-β, MDA, and GPx concentrations were measured in blood samples. The histopathologic examination was conducted by a pathologist who was unaware of the groups.Results: The biochemical results of the treatment groups (group 2 and group 3) were statistically significantly lower compared with the control group (group 1) (p < .05). The difference between the low-dose treatment group (group 2) and high-dose treatment group (group 3) was significant in terms of biochemical parameters (p < .05). The difference between group 2 and the control group was not significant in terms of histopathologic scores (p > .05), whereas the difference between the group 3 and the control group was statistically significant (p < .05).Conclusions: As a result, pentoxifylline, which has anti-inflammatory and antioxidant properties, was shown to have protective efficacy in an experimentally generated model of chronic pancreatitis.

Tu1499 Efficacy of a Small Molecule CCR2 Antagonist in Experimental Model of Chronic Pancreatitis

Tu1499 Efficacy of a Small Molecule CCR2 Antagonist in Experimental Model of Chronic Pancreatitis

Spatiotemporal Proteomic Analyses during Pancreas Cancer Progression Identifies Serine/Threonine Stress Kinase 4 (STK4) as a Novel Candidate Biomarker for Early Stage Disease

Pancreas cancer, or pancreatic ductal adenocarcinoma, is the deadliest of solid tumors, with a five-year survival rate of <5%. Detection of resectable disease improves survival rates, but access to tissue and other biospecimens that could be used to develop early detection markers is confounded by the insidious nature of pancreas cancer. Mouse models that accurately recapitulate the human condition allow disease tracking from inception to invasion and can therefore be useful for studying early disease stages in which surgical resection is possible. Using a highly faithful mouse model of pancreas cancer in conjunction with a high-density antibody microarray containing ∼2500 antibodies, we interrogated the pancreatic tissue proteome at preinvasive and invasive stages of disease. The goal was to discover early stage tissue markers of pancreas cancer and follow them through histologically defined stages of disease using cohorts of mice lacking overt clinical signs and symptoms and those with end-stage metastatic disease, respectively. A panel of seven up-regulated proteins distinguishing pancreas cancer from normal pancreas was validated, and their levels were assessed in tissues collected at preinvasive, early invasive, and moribund stages of disease. Six of the seven markers also differentiated pancreas cancer from an experimental model of chronic pancreatitis. The levels of serine/threonine stress kinase 4 (STK4) increased between preinvasive and invasive stages, suggesting its potential as a tissue biomarker, and perhaps its involvement in progression from precursor pancreatic intraepithelial neoplasia to pancreatic ductal adenocarcinoma. Immunohistochemistry of STK4 at different stages of disease revealed a dynamic expression pattern further implicating it in early tumorigenic events. Immunohistochemistry of a panel of human pancreas cancers confirmed that STK4 levels were increased in tumor epithelia relative to normal tissue. Overall, this integrated approach yielded several tissue markers that could serve as signatures of disease stage, including early (resectable), and therefore clinically meaningful, stages.

Sa1790 Imaging Macrophage-Specific Inflammation in an Experimental Model of Chronic Pancreatitis

Sa1790 Imaging Macrophage-Specific Inflammation in an Experimental Model of Chronic Pancreatitis

Differences in the Degree of Cerulein-Induced Chronic Pancreatitis in C57BL/6 Mouse Substrains Lead to New Insights in Identification of Potential Risk Factors in the Development of Chronic Pancreatitis

A frequently used experimental model of chronic pancreatitis (CP) recapitulating human disease is repeated injection of cerulein into mice. C57BL/6 is the most commonly used inbred mouse strain for biomedical research, but widespread demand has led to generation of several substrains with subtly different phenotypes. In this study, two common substrains, C57BL/6J and C57BL/6NHsd, exhibited different degrees of CP, with C57BL/6J being more susceptible to repetitive cerulein-induced CP as assessed by pancreatic atrophy, pancreatic morphological changes, and fibrosis. We hypothesized that the deficiency of nicotinamide nucleotide transhydrogenase (NNT) protein in C57BL/6J is responsible for the more severe C57BL/6J phenotype but the parameters of CP in NNT-expressing transgenic mice generated on a C57BL6/J background do not differ with those of wild-type C57BL/6J. The highly similar genetic backgrounds but different CP phenotypes of these two substrains presents a unique opportunity to discover genes important in pathogenesis of CP. We therefore performed whole mouse genome Affymetrix microarray analysis of pancreatic gene expression of C57BL/6J and C57BL/6NHsd before and after induction of CP. Genes with differentially regulated expression between the two substrains that might be candidates in CP progression included Mmp7, Pcolce2, Itih4, Wdfy1, and Vtn. We also identified several genes associated with development of CP in both substrains, including RIKEN cDNA 1810009J06 gene (trypsinogen 5), Ccl8, and Ccl6.

Brain-Derived Neurotrophic Factor Is Upregulated in Rats With Chronic Pancreatitis and Mediates Pain Behavior

We examined the role of brain-derived neurotrophic factor (BDNF) in the pathogenesis of pain in an experimental model of chronic pancreatitis (CP). Pancreatitis was induced by retrograde infusion of trinitrobenzene sulfonic acid into the pancreatic duct of adult rats. Twenty-one days after injection, BDNF expression was examined in pancreas-specific dorsal root ganglia (DRGs) by immunohistochemistry, and protein levels were quantified from DRGs and spinal cord extracts. The effects of intrathecal infusion of a neutralizing antibody to BDNF on pancreatic hyperalgesia were assessed by the sensitivity of the abdominal wall to filament probing as well as the nocifensive behavior to electrical stimulation of the pancreas. Levels of BDNF in DRGs and spinal cords (T9-13) were significantly higher in trinitrobenzene sulfonic acid rats compared with controls, accompanied by an increase in the number of pancreas-specific neurons expressing BDNF immunoreactivity. Brain-derived neurotrophic factor antagonism suppressed phospho-tropomyosin-related kinase B receptor levels in the spinal cord and significantly reduced behavioral responses in rats with CP. Brain-derived neurotrophic factor is upregulated in pancreas-specific primary afferent neurons in rats with CP, and BDNF antagonism is associated with a reduction of pain-related behavior in these animals, suggesting an important role for this neurotransmitter in the nociception of CP.

Pancreatic Regeneration by Long-Term Oral Administration of a Protease Inhibitor in a Rat Model of Chronic Pancreatitis

Background/Aims: We previously reported early-stage pancreatic histological features in an experimental chronic pancreatitis model, prepared by injecting oleic acid into the pancreatic duct. In this model, on day 2 after injection, reactive fibroblasts in association with inflammation appeared in the stroma, however, myofibroblasts, which were activated fibroblasts, were not detected. On day 4, myofibroblasts appeared in the stroma, and the lobular architecture was destroyed. On day 28, pancreatic acinar cells were completely necrotized and exfoliated, and the stroma was replaced by collagen fibers. On the other hand, it is known that the long-term oral administration of a protease inhibitor (PI) to rats causes pancreatic enlargement as a trophic effect. In this study, we investigated the trophic effect of an oral PI on the rat pancreas. And we examined the trophic effect on pancreatic regeneration in a pancreatic fibrosis model. Subjects: Male Wistar rats weighing about 200 g were used. ONO-3403 (Ono Pharmaceutical Co., Ltd., Osaka, Japan) was used as a potent oral PI. The PI action of ONO-3403 is five-fold stronger than that of camostat mesilate, the only oral PI now used clinically in Japan. Methods: (1) Normal rats were fed with standard feed or 0.1% ONO-3403-containing feed. The pancreases were removed on day 7, 14, 25. Pancreatic amylase, protein, and DNA contents, as well as pancreatic wet weights, were measured. (2) The abdominal cavity of rats was opened, 100 μl of oleic acid, a cytotoxic agent, was injected into the pancreatic duct, and the cavity was closed. Administration of 0.1% ONO-3403-containing feed was started from day 2 (A gourp) or from day 4 (B group) after injection. On day 28, the pancreases were removed and examined. Results: (1) On day 25 after ONO-3403 administration, the pancreatic wet weights increased over time by about 2.2 times. The amylase, protein, and DNA contents increased by about 3.7, 2.9, and 1.8 times, respectively. The increased protein content suggestive of “hypertrophy” was more marked than the increased DNA content suggestive of “hyperplasia”. (2) In the A group on day 28, pancreatic histological features showed the inhibition of pancreatic fibrosis and regeneration of pancreatic acinar cells. In addition, the pancreatic wet weights and contents similarly increased. However, in the B group on day 28, no improvement of pancreatic fibrosis was found. Conclusions: (1) The long-term oral administration of a potent PI showed marked trophic effects on the rat pancreas, however, the trophic effects contributed to hypertrophy rather than hyperplasia. (2) In a pancreatic fibrosis model, the long-term oral administration of a potent PI, from an early stage when no myofibroblasts appeared in the pancreatic stoma, also showed pancreatic trophic effects and led to the regeneration of pancreatic acinar cells.

S1828 Histological Study of the Early Stages of Pancreatic Fibrosis in an Experimental Model of Chronic Pancreatitis: Possibility of Pancreatic Regeneration Through the Inhibition of Inflammation in the Very Early Stages of Chronic Pancreatitis

S1828 Histological Study of the Early Stages of Pancreatic Fibrosis in an Experimental Model of Chronic Pancreatitis: Possibility of Pancreatic Regeneration Through the Inhibition of Inflammation in the Very Early Stages of Chronic Pancreatitis

Troglitazone reduces fibrosis formation and progression in an experimental model of chronic pancreatitis in mice

Trogftazone reduces fibrosis formation and progression in an experimental model of chronic pancreatitis in mice. Background: Peroxisome proliferator activated receptor gamma (PFARgamma) conu~:~ls growth, dilferentistion, and inflammation. Aim: To determine the influence of troglitazone, a figand for PPAR-gamma, on fibrosis and pancreatic damage in a mouse model of chronic pancreatitis. Methods: Mice received six hourly intraperitoneal injections ~4th 50 mg/kg cerulein (to induce pancreatins) or NACL (control), three times a week for six weeks. Seven weeks after the first injection all mice were sacrificed, Five groups were compared, i.e. A: NACL injections, B: NACL injections, chow' mixed with 0.2% troglitazone, C: cerulein iujections, D: cerulein injections, chow mLxed with troglitasone, E: cerulein injections, chow mixed with troglitazone during last 3 weeks only,. End points were pancreas weight, pancreas histology (abnormal architecture, glandular atrophy, pseudotubular complexes), collagen formation (sirius red staining to quantify fibrosis; image analysis), pancreas amylase and hydroxyproline content, TGF beta (in pancreas and plasma), and plasma soluble TNF receptor levels. The number of activated stellate cells was detected by immunohistochemistry. Results: Group C had developed chronic panereatitis after 7 weeks (all parameters P < 0.05, C vs At. Troglitazone given either for seven weeks or only for the last three weeks, reduced pancreatic damage (histology, amylase and hydroxyproline content), collagen formation, TGF beta and sTNF receptor levels and the number of activated stellate cells (P<O.05, D or E vs C; nonsignificant for D vs E). Conclusion: Troglitazone blocks activation of pancreatic stellate cells and reduces fibrosis formation and pancreatic damage in experimental chronic pancreatitis Troglitazone remains beneficial in a therapeutic setting when given after initial da:nage has been established.

The role of monocyte chemoattractant protein-1 in experimental chronic pancreatitis model induced by dibutyltin dichloride in rats.

Recently, dibutyltin dichloride (DBTC) was reported to induce pancreatic fibrosis within 28 days in rats, but it is not clear that the induced condition should be considered chronic pancreatitis. The aim of this study was to clarify whether the pancreatic fibrosis induced by DBTC can be regarded as chronic pancreatitis. Furthermore, we examined the relation of monocyte chemoattractant protein-1 (MCP-1) to the development of pancreatic fibrosis in this model. DBTC solution was injected into the right jugular vein in rats, and biochemical and histologic changes were measured at days 1, 3, 7, 14, and 28. Microscopically, inflammatory cell infiltration was evident in the pancreas at days 1 and 3, mononuclear cell infiltration was observed at days 7, 14, and 28, and pancreatic fibrosis was pronounced 7 days later. At day 28, interstitial fibrosis and atrophy of the gland and ductlike tubular complex had progressed. DBTC produced a significant decrease in the contents of pancreatic protein and amylase, whereas the pancreatic hydroxyproline content increased. Serum and pancreatic MCP-1 concentration significantly increased compared with the control group. Furthermore, the expression of PDGF mRNA in the pancreas increased following the MCP-1 elevation. These results suggest that this experimental model of pancreatic fibrosis induced by DBTC in rats was useful as a chronic pancreatitis model and that MCP-1 may play an important role in the development of pancreatic fibrosis.

The course of pancreatic fibrosis induced by dibutyltin dichloride (DBTC).

In summary, in addition to an acute interstitial pancreatitis the organotin compound DBTC induced a pancreatic fibrosis in rats. The course of the pancreatic fibrosis was studied 2-36 weeks after single i.v. treatment of rats with 6 or 8 mg/kg DBTC. The pancreatic fibrosis induced by DBTC differs from other experimental models of acute pancreatitis. Extensive infiltration by mononuclear cells is present in fibrotic areas without pancreatic atrophy or lipomatosis. The presence of chronic inflammatory lesions characterized by the destruction of exocrine parenchyma and fibrosis and in the later stages the endocrine parenchyma, indicate a chronic pancreatitis. In completion of the experimental model of the DBTC-induced acute interstitial pancreatitis in rats, the described late fibrotic effects on rat pancreas may be used as an experimental model of chronic pancreatitis.

Stenting does not decompress the pancreatic duct as effectively as surgery in experimental chronic pancreatitis

Background: In humans with chronic pancreatitis (CP), pancreatic interstitial pressure (IP) is elevated and pancreatic blood flow (PBF) is reduced. The efficacy of surgical decompression (SD) of the pancreatic duct (ie, pancreaticojejunostomy) is believed to be due to its ability to decrease IP and pancreatic vascular resistance (R p), which increases PBF. Pancreatic duct stenting (STE) also probably reduces IP and R p, which may explain its efficacy. The purpose of this study was to compare the efficacy of SD with STE. Methods: CP in cats was created by narrowing the main pancreatic duct. Six weeks later, CP and normal pancreata were isolated and perfused ex vivo under basal conditions and after secretin stimulation. In normal and CP glands, IP and perfusion pressure were measured and R p (U) was calculated. In two additional groups, the pancreatic duct was decompressed, either by stenting or by complete transection of the duct with a longitudinal capsulotomy. Results: In CP glands, IP and R p were increased and secretory output was markedly reduced compared with the normal (0.65 ± 0.30 mm Hg and 0.46 ± 0.04 U vs 3.90 ± 0.80 mm Hg and 1.68 ± 0.05 U; P < .05). Secretin administration (2 units) increased IP and R p in CP glands (6.60 ± 1.10 mm Hg and 2.87 ± 0.07 U; P < .05), but these values did not change in normal glands (0.81 ± 0.20 and 0.53 ± 0.03 U; NS). STE and SD decreased IP and R p in CP glands ( 2.20 ± 0.20 to 1.0 ± 0.40 mm Hg and 1.20 ± 0.015 to 0.90 ± 0.01 U, respectively; P < .05). Both methods prevented an increase of IP and R p after secretin administration. IP and R p decreased to a greater degree following SD, compared with STE ( P < .05). Conclusions: Both STE and SD decreased IP and R p in this experimental model of CP. However, SD was significantly more effective than STE. (Surgery 1998;124:561-7.)

Lymphocyte subsets in an experimental model of chronic pancreatitis in rats

The role of immunocompetent cells in chronic pancreatitis is poorly understood. Therefore, lymphocyte subsets were analyzed in pancreatic tissue, in peripheral blood, and in regional lymph nodes using an experimental chronic pancreatitis in rats. Methods: Pancreatitis was induced by intravenous application of dibutyltin dichloride (DBTC, 8mg/kg body weight). 5 rats per group were killed 1, 3, 5, 7, 14, 28, and 60 days after treatment. Pancreata were removed and examined immunohistochemicaUy with the APAAP technique. Peripheral blood and regional lymph nodes were obtained for isolation of lymphocytes followed by analysis of lymphocyte subsets using FACScan, Antibodies were directed to T lymphocytes, CD4+ helper T cells, CD8+ suppressor/cytotoxic T ceils, interleukin-2 receptor (CD25+), and B cells, Lymphocyte function was determined using the Concanavalin A (Con A) stimulated lymphocyte transformation assay with 3H-thymidine. Results: In DBTC-treated animals, we could demonstrate persistent infiltration of pancreatic tissue with lymphocytes. There was a predominance of CD4+ T cells compared to CD8+ T cells. However, CD8+ cells as well as CD25+ cells increased during the observation period. Number of B cells was low. During the observation period, no differences in the lymphocyte subsets in peripheral blood or in lymph nodes, were observed. Regarding lymphocyte function, we found significantly increased values of Con A induced lymphocyte transformation in regional lymph nodes in the course of pancreatitis. In peripheral blood, these changes could not be demonstrated. Conclusions: DBTC-pancreatitis was characterized by persistent infiltration of pancreatic tissue with CD4+ cells. CD8+ cells as well as activated lymphocytes increased. This indicates that suppressor/cytotoxic T cells play a role in the pathogenesis of experimental chronic pancreatitis. Regional lymph nodes were involved in the local inflammatory process. Supported by BMBF, FKZ 01/ZZ/9102

Pathophysiologic studies of experimental chronic pancreatitis in rats induced by injection of zein-oleic acid-linoleic acid solution into the pancreatic duct.

An experimental model of chronic pancreatitis was induced by a retrograde injection of a viscous solution consisting of zein-oleic acid-linoleic acid (0.05 ml/100 g body weight) into the rat pancreatic duct. Histologic and biochemical changes were investigated over a period of 6 months after induction of this model. The treated rats gained weight, but pancreatic weight decreased with time. Histologically, the widening of acinar lumen and cellular vacuolization occurred within 24 h at the parenchyma neighboring the small ducts filled with the injected solution. Degenerative parenchyma, interstitial edema, and inflammatory cell infiltration were pronounced 1 week later. Thereafter, duct-like tubular complex formation progressed, and the exocrine tissue exhibited marked atrophy of the gland with irregular fibrosis and fat replacement over a period of 6 months. Pancreatic contents of protein, amylase, DNA, and RNA markedly decreased, as did pancreatic weight, whereas hydroxyproline content increased. Oral administration of camostat did not affect pancreatic weight and contents of enzyme in this model. Urinary para-aminobenzoic acid (PABA) excretion in the BT-PABA test decreased to 54% at 6 weeks and 22% at 6 months. Although three quarters of pancreatic immunoreactive insulin (IRI) content was lost after 6 months, overt diabetes did not occur. The results suggest that an obstructive mechanism in the small ducts plays an important role in the genesis and development of chronic pancreatitis.

Expression of cytokine mRNA in an experimental model of chronic pancreatitis

Expression of cytokine mRNA in an experimental model of chronic pancreatitis

A new experimental chronic pancreatitis model in the dog: Effect of enzymatic replacement with an enteric-coated microsphere formulation (Eurobiol® 25.00 I.U.)

A new experimental chronic pancreatitis model in the dog: Effect of enzymatic replacement with an enteric-coated microsphere formulation (Eurobiol® 25.00 I.U.)

New chronic pancreatitis model with diabetes induced by cerulein plus stress in rats.

To establish a new experimental model of chronic pancreatitis (CP) with diabetes, we investigated pancreatic endocrine function, blood flow, and histopathology in CP induced by repetition of cerulein injection plus water immersion stress in rats. CP rats were treated with water immersion stress for 5 hr and two intraperitoneal injections of 20 micrograms/kg body weight of cerulein once a week for 16 weeks. In the CP group, pancreatic contents of protein, amylase, elastase, and lipase significantly decreased to 64, 38, 23, and 68% of the control group, respectively. In oral glucose tolerance test (glucose 2 g/kg body wt), blood glucose level in the CP group was 212.1 +/- 97.8 mg/dl (mean +/- SD) at 30 min and was significantly higher than the control group (126.3 +/- 15.4 mg/dl)(P < 0.05). Two of seven rats in the CP group showed an obvious diabetic insulin in the CP group was 640.1 +/- 148.7 pM, significantly lower than in the control group (1133.4 +/- 242.0 pM)(P < 0.001). However, insulin content in the pancreas was 12.37 nmol/pancreas). In CP rats, winding and dilatation of surface blood vessels and gland atrophy were evident. Marked fibrosis, fatty changes, and destruction of lobular architecture were also demonstrated microscopically, although the structure of each pancreatic islet was preserved and each islet was fully stained with anti-insulin antibody. In the CP group, pancreatic blood flow by the hydrogen gas-clearance method was 197.6 +/- 33.0 ml/min/100 g, which was significantly less than the control group (276.2 +/- 19.1 ml/min/100 g) (P < 0.001). Thus, we conclude that the CP model induced by cerulein plus stress is a new CP model with diabetes in rats, in which the glucose tolerance was impaired without loss of insulin reserve.

Canine model of chronic pancreatitis due to chronic ischemia.

An experimental model of chronic pancreatitis was produced by a chronic ischemia which was induced by ligation and separation of branches flowing into the left pancreatic lobe from the splenic artery. Macroscopic findings at 3 and 6 months after model preparation showed that the pancreas was hard, with severe inflammatory change. In the secretin-cerulein test at 3 and 6 months, the flow rate of pancreatic juice, amylase output and bicarbonate concentration were significantly reduced as compared with the controls. The histopathological findings consisted of a decrease in the pancreatic parenchyma, replacement of fat, severe inflammatory cell infiltration, extensive fibrosis and tubular complexes. As this model closely resembles human chronic pancreatitis, we conclude that ischemia is an etiological factor in chronic pancreatitis.

Initial pathophysiological changes in chronic pancreatitis induced by pancreatic ductular obstruction model.

An experimental chronic pancreatitis model was made in five dogs with chronic pancreatic fistula by injection of microspheres into the peripheral pancreatic duct. Sequential changes of pancreatic exocrine and endocrine functions with morphology were studied. Significant decreases in volume bicarbonate output and amylase output were detected in each sample collected separately on secretin and secretin cerulean stimulation. While the viscosity of pancreatic juice was significantly increased with a concomitant increase in hexosamine concentration, chronic pancreatitis was demonstrated morphologically. These results suggest that concentrated pancreatic juice caused by a decrease in volume and an increase in viscosity of pancreatic juice with a concomitant increase in hexosamine concentration brings about the progression of chronic pancreatitis in this experimental model.