Increased intestinal permeability and tight junction disruption by altered expression and localization of occludin in a murine graft versus host disease model

<p>Abstract</p> <p>Background</p> <p>Hematopoietic stem cell transplantation is increasingly performed for hematologic diseases. As a major side effect, acute graft versus host disease (GvHD) with serious gastrointestinal symptoms including diarrhea, gastrointestinal bleeding and high mortality can be observed. Because surveillance and biopsies of human gastrointestinal GvHD are difficult to perform, rare information of the alterations of the gastrointestinal barrier exists resulting in a need for systematic animal models.</p> <p>Methods</p> <p>To investigate the effects of GvHD on the intestinal barrier of the small intestine we utilized an established acute semi allogenic GvHD in C57BL/6 and B6D2F1 mice.</p> <p>Results</p> <p>By assessing the differential uptake of lactulose and mannitol in the jejunum, we observed an increased paracellular permeability as a likely mechanism for disturbed intestinal barrier function. Electron microscopy, immunohistochemistry and PCR analysis indicated profound changes of the tight-junction complex, characterized by downregulation of the tight junction protein occludin without any changes in ZO-1. Furthermore TNF-α expression was significantly upregulated.</p> <p>Conclusions</p> <p>This analysis in a murine model of GvHD of the small intestine demonstrates serious impairment of intestinal barrier function in the jejunum, with an increased permeability and morphological changes through downregulation and localization shift of the tight junction protein occludin.</p

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified