| 1. |
- Röme, Andrada, et al.
(författare)
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p38 Mitogen-activated protein kinase signalling regulates vascular inflammation and epithelial barrier dysfunction in an experimental model of radiation-induced colitis.
- 2010
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 97, s. 226-234
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:: Microvascular injury and epithelial barrier dysfunction are rate-limiting aspects in radiation enteropathy. This study examined the role of p38 mitogen-activated protein kinase (p38 MAPK) signalling in radiation-induced colitis in an experimental model. METHODS:: The p38 MAPK inhibitor SB239063 was administered to mice immediately before exposure to 20 Gy radiation. Leucocyte- and platelet-endothelium interactions in the colonic microcirculation were assessed by intravital microscopy. Levels of myeloperoxidase (MPO) and CXC chemokines (macrophage inflammatory protein (MIP) 2 and cytokine-induced neutrophil chemoattractant (KC)), and albumin leakage were quantified 16 h after irradiation. RESULTS:: Irradiation induced an increase in leucocyte and platelet recruitment, MPO activity, CXC chemokine levels and intestinal leakage. Inhibition of p38 MAPK by SB239063 decreased radiation-induced leucocyte and platelet recruitment (leucocyte rolling and adhesion by 70 and 90 per cent, both P < 0.001; that of platelets by 70 and 74 per cent, both P < 0.001). It also reduced radiation-provoked increases in colonic MPO activity by 88 per cent (P < 0.001), formation of MIP-2 and KC by 72 and 74 per cent respectively (P = 0.003 and P < 0.001), and intestinal leakage by 81 per cent (P < 0.001). CONCLUSION:: p38 MAPK is an important signalling pathway in radiation-induced colitis. Copyright (c) 2009 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
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| 2. |
- Röme, Andrada, et al.
(författare)
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Radiation-induced platelet-endothelial cell interactions are mediated by P-selectin and P-selectin glycoprotein ligand-1 in the colonic microcirculation.
- 2012
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Ingår i: Surgery. - : Elsevier BV. - 1532-7361 .- 0039-6060. ; 151:4, s. 606-611
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Antiplatelet reagents have been reported to protect against intestinal damage associated with abdominal radiotherapy, but the mechanisms behind radiation-induced platelet-endothelium interactions are not known. We sought to define the adhesive mechanisms that regulate radiotherapy-induced platelet-endothelial cell interactions in the colon. METHODS: All mice except the controls were exposed to abdominal radiation with a single dose of 20 Gray. Mice were pretreated with an isotype-matched control antibody or a monoclonal antibody directed against either P-selectin or P-selectin glycoprotein ligand-1 (PSGL-1). Platelet and leukocyte rolling and adhesion in the colon were determined by use of inverted intravital fluorescence microscopy 16 hours after radiation. Radiation-induced intestinal leakage of fluorescein isothiocyanate-conjugated dextran was examined in separate experiments. RESULTS: Immunoneutralization of P-selectin decreased radiation-provoked platelet rolling by 87% and adhesion by 63%. Moreover, inhibition of PSGL-1 decreased platelet rolling and adhesion by 77% and 83%, respectively, in animals exposed to radiation. Similarly, inhibition of P-selectin and PSGL-1 decreased radiation-induced leukocyte rolling and adhesion by more than 84% and 90%, respectively, in the colon. In contrast, inhibition of P-selectin or PSGL-1 had no impact on radiation-induced intestinal leakage. In addition, systemic depletion of platelets and leukocytes did not affect intestinal barrier dysfunction in radiated animals. CONCLUSION: This study demonstrates that radiation-provoked platelet and leukocyte accumulation are mediated in part by P-selectin and PSGL-1. Radiation-induced gut leakage, however, is independent of accumulation of platelets and leukocytes in the intestinal microvasculature.
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| 3. |
- Röme, Andrada, et al.
(författare)
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Rho kinase signalling mediates radiation-induced inflammation and intestinal barrier dysfunction.
- 2011
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 98, s. 124-131
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:: Radiotherapy is important in the management of pelvic malignancies, but radiation-induced intestinal damage is a dose-limiting factor. Microvascular injury and epithelial barrier dysfunction are considered to be rate-limiting aspects in radiation-induced enteropathy. This study investigated the role of Rho kinase signalling in radiation-induced inflammation and intestinal barrier dysfunction. METHODS:: The specific Rho kinase inhibitor Y-27632 (1 and 10 mg/kg) was given to C57BL/6J mice before challenge with 20 Gy radiation. Leucocyte- and platelet-endothelium interactions in the colonic microcirculation were assessed by intravital microscopy. Levels of myeloperoxidase (MPO) and CXC chemokines (macrophage inflammatory protein 2 and cytokine-induced neutrophil chemoattractant), and intestinal leakage were quantified after 16 h. RESULTS:: Radiation increased leucocyte and platelet recruitment, MPO activity, CXC chemokine production and intestinal leakage. Y-27632 significantly reduced radiation-induced leucocyte rolling and abolished adhesion; it also decreased platelet rolling and adhesion by 55 and 74 per cent respectively (P < 0·050). Inhibition of Rho kinase signalling significantly decreased radiation-provoked formation of CXC chemokines, MPO activity by 52 per cent, and intestinal leakage by 67 per cent (P < 0·050). CONCLUSION:: Rho kinase activity constitutes an important signalling mechanism in radiation-induced inflammation and intestinal barrier dysfunction. Copyright © 2010 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
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