Oral glutamine supplementation improves intestinal permeability dysfunction in a murine acute graft-vs.-host disease model.

Although a profound barrier dysfunction has been reported, little is known about the pathophysiological mechanism evoking gastrointestinal graft-vs.-host disease (GI-GvHD) and apparent therapeutic options. The aim of this study was to evaluate the influence of oral glutamine on the course of GI-GvHD in an acute semiallogenic graft-vs.-host disease (GvHD) in irradiated B6D2F1 mice. An acute semiallogenic GvHD was induced by intraperitoneal injection of lymphocytes from C57BL/6 mice to irradiated B6D2F1 mice. Half of the GvHD animals received oral glutamine supplementation for 6 days started at the time of lymphocyte transfer. Six days after induction of the semiallogenic GvHD, jejunum specimens were prepared. The expression of the proinflammatory cytokine TNF-α and the tight junction protein occludin was investigated by PCR. Histological changes along with the apoptotic response were evaluated and intestinal permeability was assessed. Animals with GvHD showed a strong increase in paracellular permeability as a sign of the disturbed barrier function. TNF-α expression was significantly increased and the expression of the tight junction protein occludin decreased. GvHD led to mucosal atrophy, crypt hyperplasia, crypt apoptosis, and a disintegration of the tight junctions. Glutamine-treated mice showed reduced expression of TNF-α, increased occludin expression, fewer histological changes in the jejunum, smaller number of apoptotic cells in the crypt, and reduced gastrointestinal permeability. In conclusion, oral glutamine seems to have beneficial effects on the severity of inflammatory changes in the course of GvHD and might be a therapeutic option.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Agenesis of the Gallbladder: Role of Clinical Suspicion and Magnetic Resonance to Avoid Unnecessary Surgery.

Isolated agenesis of the gallbladder is usually a rare asymptomatic anatomical variation, with an estimated incidence of 10-65 per 100,000. Females are more commonly affected (ratio 3: 1), with the disease typically presenting in the second or third decade of their life. Despite an absent gallbladder, half of the patients present with symptoms similar to biliary colic, which is poorly understood. The rarity of this condition combined with its clinical and radiological features often lead to a wrong preoperative diagnosis so that many patients undergo unnecessary operative intervention. Herein, we present the case of a 56-year-old female with a typical biliary colic who was diagnosed to have gallbladder agenesis. Computed tomography and magnetic resonance cholangiopancreatography allowed correct treatment and prevented an unnecessary intervention.

Anti-TNF-α antibodies improve intestinal barrier function in Crohn's disease.

BACKGROUND AND AIMS: Intestinal barrier function in Crohn's disease patients and their first degree healthy relatives is impaired. The increased intestinal permeability may result in an enhanced mucosal immune response and thereby aggravate intestinal inflammation. Humanised anti-TNF-α antibodies have been shown to be effective in the treatment of active Crohn's disease and in the treatment of entero-cutaneous fistula. The aim of the present study was to investigate the influence of anti-TNF-α antibody (infliximab) treatment on the intestinal barrier function of patients with active Crohn's disease. METHODS: The differential intestinal uptake of lactulose and mannitol was measured to quantify intestinal permeability in patients with long standing active Crohn's disease (n=17) directly before and seven days after treatment with infliximab (5 mg/kg bodyweight). In parallel, intestinal permeability was studied in a healthy control group (n=20). Serum samples were analysed with pulsed amperometric detection after separation on an anion exchange column. RESULTS: Intestinal permeability was significantly increased in all patients with Crohn's disease (L/M ratio 0.24±0.17) prior to infliximab treatment compared to the control group (L/M ratio 0.01±0.02; p-value <1×10(-7)). Treatment of patients with infliximab resulted in a marked decrease of intestinal permeability as measured by L/M ratio from 0.24±0.17 before to 0.02±0.02 (p-value <1×10(-7)) seven days after infliximab application. CONCLUSIONS: Treatment with anti-TNF-α antibodies improved impaired intestinal barrier function in patients with Crohn's disease. This effect may correlate to the well documented anti-inflammatory effect of TNF-α blockade in this intestinal disease.

Gastric emptying time of fluids and solids in healthy subjects determined by 13C breath tests: influence of age, sex and body mass index.

BACKGROUND AND AIM: Disturbance of gastric emptying leads to a variety of symptoms. Furthermore, gastric motility disorders might play a role in the pathophysiology of functional dyspepsia. In previous studies 13C breath tests were validated as non-invasive tools in the measurement of gastric emptying time. So far, reliable reference values of healthy subjects are missing and the impact of constitutional traits (age, sex, body mass index [BMI]) needs to be clarified. METHODS: A study was conducted in 90 healthy individuals (45 men, 45 women) that assessed the correlation of parameters of gastric emptying (half gastric emptying time [T1/2] and time of fastest gastric emptying [T(lag)]) with age, sex and BMI for fluid and solid test meals by 13C breath tests. 100 mg of sodium acetate or sodium octanoate, respectively, were used as tracers. Breath probes were analyzed by non-dispersive infrared spectroscopy. RESULTS: The mean +/- SD of half gastric emptying time (T1/2) of a fluid test meal was determined to be 80.5 +/- 22.1 min and for T(lag) to be 40.3 +/- 10.2 min. However, the T1/2 and T(lag) of solid meals did not fit to normal distribution and thus median and percentiles were determined. The median time of T1/2 for solids was 127 min (25-75% percentiles: 112.0-168.3 min) and 81.5 min for T(lag) (25-75% percentiles: 65.5-102.0 min). No significant correlation was found between gastric emptying and age, sex or BMI. CONCLUSION: This is the first study to examine gastric emptying in an adequate number of healthy subjects by 13C breath tests. No significant correlation was found with age, sex and BMI. Although there is considerable standard deviation in gastric emptying time, these results may nevertheless serve as reference values for further studies.

Life-threatening chronic enteritis due to colonization of the small bowel with Stenotrophomonas maltophilia.

Chronic diarrheal illness and malabsorption are challenging diagnostic and clinical problems. The identification of the causative pathogens that are involved in gastrointestinal infections is often difficult. It took 85 years after the first description of a case of intestinal lipodystrophy by Georg Whipple in 1907 until the causative bacterium was characterized by using molecular genetics techniques. We here report the complicated clinical course of a young patient with chronic diarrhea accompanied by severe, life-threatening malabsorption with extensive weight loss. Histology and glucose hydrogen breath test were suggestive of a bacterial overgrowth syndrome in the small bowel, but standard culture-based techniques and serology failed to identify the causative bacteria. Thus, bacterial ribosomal DNA (16S ribosomal DNA) was extracted from duodenal biopsy samples and analyzed by community fingerprinting and species-specific polymerase chain reaction. Stenotrophomonas maltophilia was identified as the cause of chronic infectious enteritis. Only specific long-term antibiotic treatment with co-trimoxazole had a durable clinical effect and led to normalization of 16S ribosomal DNA profiles. This case shows the role of rare and uncommon bacteria in refractory and chronic human gastrointestinal infections. Genomic techniques, including 16S-based single-strand conformation polymorphism analysis, will play an increasing role in the diagnosis of chronic infections with facultatively pathogenic bacteria or in the clinical analysis of complex bacterial communities such as the intestinal bacterial microflora. Future enhancements in detection techniques will show that chronic bacterial infections are more frequent as a cause of gastrointestinal malfunction than commonly thought.

The role of tissue transglutaminase (transglutaminase type II) for the intestinal manifestations of murine semi-allogenic graft-versus-host disease.

The intestinal manifestation of acute murine semi-allogenic graft-versus-host (GvH) disease is characterized by the occurrence of lymphocytic infiltrates in the lamina propria, by crypt hyperplasia and villous atrophy. In a histological respect, this animal model resembles human celiac disease. Tissue transglutaminase (tTG) (transglutaminase type II) has been identified to be the major B cell autoantigen in celiac disease. Furthermore, tissue transglutaminase has been implicated to be involved in its pathogenesis. Therefore, we aimed to investigate whether tissue transglutaminase is expressed in the intestines of GvH animals and whether its inhibition has any effect on the intestinal histology. Sera of patients with celiac disease and anti-tTG antibodies were purified. These antibodies were used for immuno-histochemistry of jejunal cryosection from GvH and syngenic control animals at day 6 after lymphocyte transfer. Furthermore, GvH mice were treated with antitTG antibodies and with the inhibitor of tissue transglutaminase monodansyl-cadaverine. The effect of this treatment on the development of crypt hyperplasia and villous atrophy were examined by light microscopy of hematoxylin-eosin (H&E) stained jejunal paraffin sections. We found a strong subepithelial expression of tissue transglutaminase in GvH animals but not in syngenic control mice. The localization of tTG seemed to be associated with the extracellular matrix (ECM). However, neither the treatment of GvH animals with anti-tTG antibodies nor the application of mono-dansyl-cadaverine prevented the development of crypt hyperplasia and villous atrophy. Similar to the situation in human celiac disease tissue, transglutaminase is highly expressed in the intestine of animals undergoing a semi-allogenic graft-versus-host reaction. However, this enzyme is probably not involved in the development of crypt hyperplasia and villous atrophy in this animal model.

On the pathogenesis and clinical course of mesenteric lymph node cavitation and hyposplenism in coeliac disease.

BACKGROUND: Coeliac disease is a disorder characterised by malabsorption related to abnormal small bowel structure and intolerance to gluten. There are several reports of an increased risk for malignancy in coeliac disease and its relation to gluten-free, reduced gluten, or normal diet. While a normal diet is associated with an excess of cancer of the mouth, pharynx, oesophagus, and also of lymphoma, treatment with a gluten-free diet restores the cancer risk back to normal. PATIENT: In the present study, we report on a 63-year-old female patient with a history of coeliac disease for twenty years who presented with persistent diarrhoea, weight loss, and an abdominal mass. RESULTS: The gastroenterological work-up revealed small bowel mucosal atrophy, absence of functional splenic tissue, and evidence for an involution of a mesenteric lymph node, termed cavitation. DISCUSSION: This triad has been previously described to represent a rare disease entity related to coeliac disease. We report a two-year follow-up and a review of the literature on the pathogenesis, prognosis, and therapeutical implications of this disease entity.