| 11. |
- Awla, Darbaz
(författare)
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Signaling and Adhesive Mechanisms in Acute Pancreatitis
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Acute pancreatitis (AP) is an inflammatory disease with variable severity ranging from mild interstitial edematous to severe necrotizing disease. The overall mortality rate of AP is 8-9%. Specific treatment of AP is lacking which is partly related to an incomplete understanding of the basic pathophysiology behind the disease. It is widely held that premature intra-cellular trypsinogen activation and leukocyte recruitment play key roles in the pathophysiology of the AP. However, the signaling and adhesive mechanisms remain elusive. The aim of this thesis was to investigate the signaling and adhesive mechanisms in AP. In this thesis, biliary pancreatitis was induced by retrograde infusion of taurocholate into the pancreatic duct in different mice strains to elucidate the role of toll-like receptor 2 (TLR2), TLR4, lymphocyte function antigen-1 (LFA-1), matrix metalloproteinases (MMPs) and Rho-kinase as well as nuclear factor of activated T-cell (NFAT) signaling in AP. We found that TLR4 but not TLR2 plays a role in AP. LFA-1 adhesive mechanisms play a role in tissue damage and leukocyte recruitment but not trypsinogen activation. Furthermore, neutrophil-derived MMP-9 mediates tissue damage and neutrophil-dependent trypsinogen activation. Rho-kinase signaling regulates trypsinogen activation, leukocyte recruitment and tissue damage in AP. Moreover, NFATc3 is activated and translocated to the acinar cell nucleus and regulates trypsinogen activation, leukocyte recruitment and tissue damage in AP. Taken together, the results of this thesis demonstrate that signaling and adhesive mechanisms are of particular importance in the pathophysiology of AP and could be used as useful targets in the management of patients with AP.
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| 12. |
- Awla, Darbaz, et al.
(författare)
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TLR4 but not TLR2 regulates inflammation and tissue damage in acute pancreatitis induced by retrograde infusion of taurocholate.
- 2011
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1420-908X .- 1023-3830. ; 60, s. 1093-1098
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Neutrophil infiltration is a key regulator in the pathophysiology of acute pancreatitis (AP), although the impact of Toll-like receptors (TLRs) in AP remains elusive. The aim of this study was to define the role of TLR2 and TLR4 in leukocyte recruitment and tissue damage in severe AP. EXPERIMENTAL DESIGN: AP was induced by retrograde infusion of sodium taurocholate into the pancreatic duct in wild-type, TLR2- and TLR4-deficient mice. Samples were collected 24 h after induction of AP. RESULTS: Taurocholate challenge caused a clear-cut pancreatic damage characterized by increased acinar cell necrosis, neutrophil infiltration, focal hemorrhage and edema formation, as well as increased levels of blood amylase and CXCL2 (macrophage inflammatory protein-2) in the pancreas and serum. Moreover, challenge with taurocholate increased activation of trypsinogen in the pancreas. Notably, TLR2 gene-deficient mice exhibited a similar phenotype to wild-type mice after challenge with taurocholate. In contrast, tissue damage, pancreatic and lung myeloperoxidase (MPO) activity, serum and pancreatic levels of CXCL2 as well as blood amylase were significantly reduced in TLR4-deficient mice exposed to taurocholate. However, taurocholate-induced activation of trypsinogen was intact in TLR4-deficient mice. CONCLUSION: Our data suggest a role for TLR4 but not TLR2 in the pathogenesis of severe AP in mice.
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| 13. |
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| 14. |
- Hartman Magnusson, Hannes, et al.
(författare)
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P-selectin mediates neutrophil rolling and recruitment in acute pancreatitis
- 2012
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 99, s. 246-255
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Tidskriftsartikel (refereegranskat)abstract
- Background: The adhesive mechanisms regulating leucocyte-endothelium interactions in the pancreas remain elusive, but selectins may play a role. This study examined the molecular mechanisms mediating leucocyte rolling along the endothelium in the pancreas and the therapeutic potential of targeting the rolling adhesive interaction in acute pancreatitis (AP). Methods: Pancreatitis was induced by retrograde infusion of 5 per cent sodium taurocholate into the pancreatic duct, repeated intraperitoneal administration of caerulein (50 μg/kg) or intraperitoneal administration of L-arginine (4 g/kg) in C57BL/6 mice. A control and a monoclonal antibody against P-selectin were administered before and after induction of AP. Serum and tissue were sampled to assess the severity of pancreatitis, and intravital microscopy was used to study leucocyte rolling. Results: Taurocholate infusion into the pancreatic duct increased the serum level of trypsinogen, trypsinogen activation, pancreatic neutrophil infiltration, macrophage inflammatory protein (MIP) 2 formation and tissue damage. Immunoneutralization of P-selectin decreased the taurocholate-induced increase in serum trypsinogen (median (range) 17·35 (12·20- 30·00) versus 1·55 (0·60-15·70) μg/l; P = 0·017), neutrophil accumulation (4·00 (0·75-4·00) versus 0·63 (0-3·25); P = 0·002) and tissue damage, but had no effect on MIP-2 production (14·08 (1·68-33·38) versus 3·70 (0·55-51·80) pg/mg; P = 0·195) or serum trypsinogen activating peptide level (1·10 (0·60-1·60) versus 0·45 (0-1·80) μg/l; P = 0·069). Intravital fluorescence microscopy revealed that anti-P-selectin antibody inhibited leucocyte rolling completely in postcapillary venules of the inflamed pancreas. Conclusion: Inhibition of P-selectin protected against pancreatic tissue injury in experimental pancreatitis. Targeting P-selectin may be an effective strategy to ameliorate inflammation in AP. © 2011 British Journal of Surgery Society Ltd.
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