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

Antiviral effect of prolonged intermittent lymphoblastoid alpha interferon treatment in chronic hepatitis B

In a European multicentre study 40 patients with HBeAg positive chronic hepatitis B virus (HBV) infection were treated with 5 mega units of lymphoblastoid alpha-interferon daily according to the following regimen: a four week primer course, four weeks of rest and a second course lasting 16 to 30 weeks. After 52 weeks of follow up, a response (HBeAg seroconversion and HBV-DNA negativity) was observed in 22 patients (55%). HBsAg seroconversion occurred in five patients (12.5%). One patient exhibited a relapse for serum HBeAg and HBV-DNA after cessation of treatment. According to a response prediction model, the observed response rate was not related to the selection of patients likely to respond. The initial interferon course induced a reduction of the serum HBV-DNA and HBeAg levels of 87% and 18%, respectively, leading to a significantly lower level of viral replication activity at the start of the second longterm course compared with baseline. After 24 weeks of follow up (week 16 of the second course), 19 (48%) patients exhibited a response, 13 (32%) a partial response (HBeAg < 50% of initial level or HBV-DNA negative) and 8 (20%) no response. For eight of the 13 partial responders treatment was stopped at week 24 and viral replication rebounded to pretreatment values. In the last five partial responders prolongation of therapy up to week 38 led to a definite response and HBsAg seroconversion in three of the five patients. The results of this study suggest that a short primer course and prolongation of therapy may help to enhance the response rate of alpha-interferon therapy for chronic hepatitis type