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|Title:||Gut barrier dysfunction after hemorrhagic shock||Authors:||DAISSORMONT, Isabelle||Advisors:||BUURMAN, W.A.||Issue Date:||2007||Publisher:||tUL||Abstract:||Introduction: Hemorrhagic shock is a frequent complication in trauma patients, after gastrointestinal bleeding and major surgery. Hemorrhagic shock is associated with end organ damage, caused by hypoperfusion and local and systemic inflammation. The intestine is one of the first organs affected by hemorrhagic shock. An early event in intestinal damage is gut wall integrity loss, including the opening or breakdown of tight junctions. In the first part of the study, the sequence of events in the gut after hemorrhagic shock and the underlying mechanism causing tight junction loss were studied. In the second part, the use of the transmembrane tight junction protein, claudin-3, as urinary marker for intestinal tight junction loss was investigated. Methods: Sprague-Dawley rats were subjected to hemorrhagic shock and sacrificed 15, 30, 60 and 90 minutes after shock. Control rats were sacrificed without intervention. Tight junction integrity was studied by immunofluorescence (IF) and western blot analysis (WB) of tight junction proteins ZO-1 and claudin-3 in the ileum. The underlying mechanism of tight junction loss was investigated by studying ADF activation by WB and changes in actin cytoskeleton by IF. Epithelial cell injury was investigated by ileal lipid binding protein (ILBP) detection in epithelial cells and plasma. Intestinal barrier function was studied by investigating intestinal permeability to macromolecules and bacterial translocation. Finally, local and systemic inflammation were studied by investigating neutrophil influx and by measuring TNF- plasma concentration by ELISA respectively. For the second part of the study, claudin-3 urine levels were semi-quantitatively analyzed by WB. To investigate whether claudin-3 detected in the urine is released by intestinal tight junction loss and not by tight junction loss in the liver and kidney, tight junction integrity loss in the liver and kidney was studied by IF and WB. Results: The first part of the study shows that hemorrhagic shock leads to neutrophil influx from 15 minutes after shock. From this time point, hemorrhagic shock causes a significant upregulation of activated ADF and the turnover of F-actin (filamentous or polymeric actin) into G-actin (globular or monomeric actin). This is followed by a significant loss of tight junction proteins claudin-3 from 30 minutes and ZO-1 from 60 minutes after shock. Epithelial ILBP content decreases from 60 minutes after shock. Intestinal barrier function loss from 60 minutes after shock is represented by bacterial translocation and from 90 minutes after shock by enhanced permeability to horseradish peroxidase (HRP). Plasma TNF- levels are significantly elevated from 60 minutes after shock. The results of the second part of the study show that claudin-3 urine levels are significantly increased 30, 60 and 90 minutes after hemorrhagic shock. Tight junction integrity in the liver and kidney is maintained 15, 30, 60 and 90 minutes after hemorrhagic shock. Discussion: This study gives more insight into the sequence of events in the gut after hemorrhagic shock. Hemorrhagic shock leads to neutrophil influx followed by intestinal tight junction integrity loss after upregulation of activated ADF and consequent actin cytoskeleton degradation. This is followed by bacterial translocation and systemic hyperinflammation. In addition, this study indicates that intestinal claudin-3 loss is followed by an increase in claudin-3 urine levels and that claudin-3 integrity in the liver and kidney is maintained, suggesting that claudin-3 can be used as urinary marker for intestinal tight junction loss.||Notes:||Master in de Biomedische wetenschappen - Klinische en moleculaire wetenschappen||Document URI:||http://hdl.handle.net/1942/1943||Category:||T2||Type:||Theses and Dissertations|
|Appears in Collections:||Master theses|
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checked on May 26, 2022
checked on May 26, 2022
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