Abstracts

2011 Pancreatology (Print)  
Calcium overload causing mitochondrial damage determines acinar cell fate in acute pancreatitis. Cyclophilin-D (Cyp-D) modulates the mitochondrial permeability transition pore (mPTP), determining cell fate in response to injury. We have investigated the role of the mPTP in pancreatitis using genetic (Cyp-D KO) and pharmacological (Alisporivir, DEB025) inhibition of Cyp-D. Methods: Confocal fluorescence microscopy of isolated pancreatic acinar cells from Ppif-/-and wild type mice was used to
more » ... ure cytosolic calcium ([Ca2+]c), NAD(P)H autofluorescence, mitochondrial membrane potential (∆ψm) and cell death in response to taurolithocholic acid 3-sulphate (TLC-S) or CCK-8 hyperstimulation. Murine pancreatitis was induced by ductal bile acid infusion or cerulein injections (7 x 50 μg/kg ip) and DEB025 (10 mg/kg or 100 mg/kg after disease induction) tested as treatment, using standardised assessment of plasma amylase, IL6 and pancreatic histopathology (> 6 all groups). Results: TLC-S or CCK-8 induced marked elevation in [Ca2+]c, falls in ∆ψm and NADH levels, and acinar cell necrosis pathway activation. Cyp-D KO preserved cell function and reduced necrosis (p<0.05) but not apoptosis pathway activation. The severity of pancreatitis in both models was greatly reduced (all parameters p<0.05) in Cyp-D KO mice and DEBO25-treated wild type mice. Conclusion: Inhibition of Cyp-D preserves mitochondrial function and protects pancreatic acinar cells from pancreatitis toxins, an approach that has potential as a treatment for acute pancreatitis. Introduction: At present no simple, reliable model of murine alcoholic pancreatitis exists. Non-oxidative metabolites of alcohol, fatty acid ethyl esters, are synthesized in the pancreas by enzymes which conjugate ethanol (EtOH) to fatty acids and have been implicated as mediators of acute pancreatitis. We have characterised a novel acute pancreatitis model induced by concomitant administration of EtOH and fatty acid (palmitoleic acid: POA) in mice. Methods: CD1 mice (30-35 g) were injected intraperitoneally twice one h apart, either with normal saline (50 μl), or 1.32 g/kg pure EtOH, or 1.32 g/kg EtOH + 0.25 mg/kg POA, or 1.32 g/kg EtOH + 2 mg/kg POA. The severity of acute pancreatitis was assessed at 2, 6, 12, 24 and 48 h after the first injection. The peak serum EtOH concentration was quantified by enzymatic assay. Results: The peak serum EtOH concentration achieved was 35.6±4.9 mM in the EtOH alone group. Saline, EtOH alone, or EtOH with the lower concentration of POA caused no discernable pancreatic injury. In contrast, EtOH with the higher concentration of POA induced significant increases of serum amylase (peak at 12 h), pancreatic trypsin and myeloperoxidase activity, accompanied by marked histopathological changes that peaked at 24 h. All parameters decreased at 48 h. Conclusion: Our results indicate that concomitant administration of EtOH and POA causes acute pancreatitis. Since this novel model may parallel clinical acute alcoholic pancreatitis, it could be a useful tool to study alcoholinduced acute pancreatitis. Background: Autoimmune pancreatitis (AIP) is a discrete entity of pancreatitis that is characterized by a steroid-responsive, fibroinflammatory condition that often involves multiple organs. Animal models have been used to study the autoimmune mechanism of AIP. Aim: To investigate the pathogenesis of murine AIP induced by tolllike receptor (TLR) stimulation. Methods: Six-week-old female MRL mice were injected intraperitoneally with polyinosinic polycytidylic acid (poly I:C) or lipopolysaccharide (LPS) at doses of 5 mg/kg body weight twice weekly for 12 weeks. The mice were killed and the severity of pancreatitis was graded using a histological scoring system. Serum cytokine levels of mice with pancreatitis and mice that were given a single injection of TLR ligands were measured using enzyme-linked immunosorbent assays. The effect of TLR stimulation on the development of pancreatitis was also examined using C57BL/6 interleukin (IL)-10-deficient (KO) mice. Results: Administration of poly I:C accelerated the development of pancreatitis in MRL mice, but LPS did not. Serum levels of IL-10 and IL-12 were significantly elevated in mice with AIP. A single injection of LPS markedly increased serum levels of IL-10, interferon-γ, tumor necrosis factor-α and IL-12 compared with those of poly I:C-treated mice. Treatment with poly I:C and LPS induced pancreatitis in IL-10 KO mice, but not in wild-type mice. The severity of pancreatitis was greater in mice treated with LPS than in mice treated with poly I:C. Conclusion: Imbalance between proinflammatory and anti-inflammatory cytokines induced by repeated stimulation of innate immunity leads to autoimmunity in the pancreas of mice. Background: Animal models help study the pathophysiological mechanisms of acute pancreatitis (AP). Caerulein induced AP is a common model in mice. Generally, 8-12 injections of 50 μg of caerulein every hour are used to induce AP but there is a wide variability in the dosage and duration of caerulein from 3 to 12 injections. No comparative data are available between low and high dosage of caerulein. Objective: To compare the severity of AP between 4 and 8, hourly injections of caerulein. Methods: 24 adult male Swiss albino mice were divided into 3 groups of 8 animals each: Group I was given saline injections; group II was given hourly intra-peritoneal injections of caerulein (50 μg/kg) for 4 hours; and group III was given the same treatment for 8 hours. The animals were sacrificed 1 hour after the last injection. Severity of AP was assessed by serum amylase, lung myeloperoxidase, histopathological score, and electron microscopic examination. Results: Both low and high dose caerulein induced necrotizing pancreatitis although the severity of pancreatitis was more in the high dose group. The histopathological scores were: group I 0.25±0.1, group II 8.85±0.5 and group III 9.82±0.5. The amylase levels were high in both low and high dose caerulein groups (39.69±3.38 U/mL vs. 53.75±2.44 U/mL; p = NS). Lung myeloperoxidase levels were higher in the high dose group (20.65 vs. 2.35, p = 0.03). Electron microscopic examination showed autophagic vacuoles, apoptosis and necrosis in both the low and high dose groups. Conclusion: Caerulein given for 4 hours induces severe necrotizing pancreatitis sufficient to study the pathophysiological events and facilitates early completion of experiment. Background: Evidences suggest that proinflammatory cytokines such as IL-1, TNFα, IL-6 and IL-8 act as mediators of local and systemic manifestations in acute pancreatitis and correlate with the severity of the disease. The mechanisms of myocardial injury in acute pancreatitis are not completely understood. The production in situ into the myocardium of cytokines may lead to acute myocardial damage with functional changes and, eventually, chronic sequelae. Aim: To evaluate the histological and functional changes of the heart in acute pancreatitis and to correlate with the production of cytokines in situ into the myocardium. Methods: Adult Wistar male rats were subjected to experimental acute pancreatitis. Myocardial function was evaluated by using echocardiography, rats were sacrificed for biochemical determination, histochemical and TGFα gene expression study at 2, 4, 12 and 24 h and 15 days. Results: We observed decrease diastolic and systolic function, decrease in ventricular compliance with fibromuscular lesions and elevation of TGFα mRNA levels demonstrating the occurrence of fibrosis and cellular repair. Conclusion: We conclude that in acute pancreatitis there are function damage and increasing TGFα, probably related to myocardial reparation process. Pancreatology 2011;11(suppl 1):1-80 3 Abstracts
doi:10.1159/000324201 fatcat:onjgvd66y5d75m73k4rpdmr4ei