Eckhard Stüber

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.

Involvement of OX40-OX40L interactions in the intestinal manifestations of the murine acute graft-versus-host disease

BACKGROUND & AIMS The intestinal histology of murine semiallogeneic graft-versus-host (GVH) disease is characterized by lymphocytic infiltrates, crypt hyperplasia, and villous atrophy. Mechanisms of T cell-mediated changes of the mucosal architecture were investigated. METHODS The rate of cellular apoptosis and proliferation, changes in the composition of extracellular matrix (ECM), and the role of OX40-OX40L interactions in the pathogenesis of villous atrophy and crypt hyperplasia were examined. RESULTS The rate of apoptosis and the number of proliferating cells were significantly increased in GVH animals compared with control animals. In addition, expression of tenascin, an ECM component, was down-regulated in GVH animals. Inhibition of OX40-OX40L interactions in GVH animals by administration of an OX40-Ig fusion protein completely prevented the development of crypt hyperplasia and villous atrophy in GVH animals. Tenascin expression was up-regulated in OX40-Ig-treated mice compared with GVH animals, suggesting an important function of this ECM component in mucosal repair. CONCLUSIONS The OX40-OX40L interaction is crucial in the pathogenesis of GVH, a T cell-mediated intestinal disease. The data suggest that the ECM component tenascin is probably relevant for the regeneration and maintenance of intestinal tissue architecture.

Intestinal crypt cell apoptosis in murine acute graft versus host disease is mediated by tumour necrosis factor α and not by the FasL-Fas interaction: effect of pentoxifylline on the development of mucosal atrophy

BACKGROUND Murine T cell mediated acute semiallogeneic graft versus host disease (GVHD) is characterised by lymphocytic infiltrates, crypt hyperplasia, and villous atrophy. It has been shown that programmed cell death (apoptosis) of the crypt epithelium takes place during the intestinal manifestation of acute GVHD. AIMS To investigate which of the two most investigated inductors of apoptosis (Fas ligand (FasL) and tumour necrosis factor α (TNF-α)) is responsible for the induction of apoptosis in this animal model. METHODS Animals undergoing acute semiallogeneic GvH reaction were treated with neutralising anti-TNF-α, two different anti-FasL antibodies, or pentoxifylline. RESULTS Anti-TNF-α application inhibited the appearance of apoptotic cells in the intestinal mucosa, whereas anti-FasL antibodies had no influence on mucosal apoptosis. In addition, the transfer of FasL deficient (gld) donor lymphocytes still induced crypt cell apoptosis, villous atrophy, and crypt hyperplasia. Furthermore, when the animals were treated with pentoxifylline, a known inhibitor of TNF-α secretion in vitro and in vivo, there was significant normalisation of the intestinal morphology accompanied by inhibition of epithelial apoptosis. CONCLUSIONS The FasL-Fas interaction is not involved in the induction of apoptosis during acute GVHD. However, neutralisation of TNF-α by an antibody or by pentoxifylline inhibits the occurrence of apoptosis and of mucosal atrophy in this animal model. These results have implications for the treatment of immunologically mediated human atrophic gut diseases—for example, diet refractory cases of coeliac disease.

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

BackgroundHematopoietic 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.MethodsTo 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.ResultsBy 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.ConclusionsThis 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.

Identification of CCK-B/gastrin receptor splice variants in human peripheral blood mononuclear cells

There is increasing evidence for a direct interaction of the enteric nervous and immune system. Receptors for neuropeptides such as VIP, somatostatin, and substance P have been characterised in human immuno-haematopoietic cells but little is known about the functional significance and expression of receptors for cholecystokinin (CCK) on cells of the immune system. There are only few studies that describe the expression of CCK receptors on human leukaemia-derived cell lines but the receptor structure and function in normal leukocytes have not been clearly established. We therefore sought to determine CCK receptor expression, structure, and function in nontransformed human peripheral blood mononuclear cells.Full-length cDNA clones encoding the human CCK-A and CCK-B/gastrin receptor are expressed in peripheral blood mononuclear cells from healthy volunteers without haematopoietic malignancy. In addition to wild-type CCK-B/gastrin receptor cDNAs, we isolated a splice variant with an in frame insertion of 69 amino acids within its putative third intracellular receptor loop. Dideoxy sequence analysis revealed that the cDNA of this splice variant comprises exons 1-4 but retains intron 4 (207 bp) in the absence of mutations within the splice donor sites. Transient expression of this splice variant in COS-7 cells reveals wild-type affinity for CCK-8, Gastrin-17, and antagonist L-365,260. Affinity for glycine-extended gastrin-17 was not increased when compared to the wild-type CCK-B/gastrin receptor. In vitro, gastrin decreased 3H-thymidine labelling in phytohaemagglutinin-pretreated mononuclear cells at a half-maximally effective concentration of 1.5 nM. We also isolated a cDNA encoding another splice variant of the CCK-B/gastrin receptor with a 158 bp deletion of the entire exon 4 sequence. We conclude that wild-type transcripts of both CCK receptor subtypes and splice variants of the CCK-B/gastrin receptor are expressed in nontransformed human mononuclear cells and that gastrin exhibits antiproliferative effects.

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.

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

BACKGROUND AND AIMS Intestinal barrier function in Crohns 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 Crohns 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 Crohns disease. METHODS The differential intestinal uptake of lactulose and mannitol was measured to quantify intestinal permeability in patients with long standing active Crohns 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 Crohns 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 Crohns disease. This effect may correlate to the well documented anti-inflammatory effect of TNF-α blockade in this intestinal disease.

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.

Infected bile-induced acute pancreatitis in rabbits. The role of bacteria.

SummaryConclusionsBacteria species commonly found in bile of patients with choledocholithiasis render human bile toxic to the pancreas. The severity of infected bile-induced acute pancreatitis depends on the bacterial species. Infected bile-induced acute pancreatitis turns into a sterile inflammation within 10 d.BackgroundFlow of bile into the pancreatic duct was proposed to cause some forms of gallstone pancreatitis. The development of bile-induced acute pancreatitis at physiologic ductal pressure is known to depend on the bacterial infection of bile. In this study, we investigated the effect of a variety of bacteria species commonly found in bile of patients with choledocholithiasis upon the pancreatic toxicity of human bile. The time-course of pancreatic infection in infected bile-induced acute pancreatitis was also analyzed.MethodsIn rabbits, the pancreatic duct was kept obstructed throughout the experiment. After 24 h, 50 μL of pancreatic juice was obtained from the congested pancreatic duct and replaced with the same quantity of infected human bile. Bile contained bacteria (107 microorganisms/μL) of species frequently found in choledochal secretions of patients with gallstone disease. Effects on pancreatic morphology were studied after 48 h. In another experiment, the number ofEscherichia coli/mg of pancreatic tissue was determined in a time sequence study following exposure of the rabbit pancreatic duct to 50 μLE. coli-infected bile (107 microorganisms/mL) and temporary (12 h) or permanent duct obstruction.ResultsSterile bile was not harmful to the pancreas. Infected bile caused an interstitial-edematous pancreatitis with occasional acinar necrosis. The severity of acute pancreatitis depended on the bacterial species. Following pancreatic duct exposure toE. coli-infected bile, there was complete clearance of the bacteria from the gland with a concomitant interstitial leukocyte infiltration within a period of 2–10 d.

Endoscopic-guided capsule endoscopy in a patient with small-bowel varices after Whipple's operation

2001;88:773-86. 12. Shimoji H, Shiraishi M, Hiroyasu S, Isa T, Kusano T, Muto Y. Common bile duct blood clot: an unusual cause of ductal filling defects for calculi. J Gastroenterol 1999;34:420-3. 13. Dos Reis L, De Almeida CC. Post-cholecystectomy jaundice due to intracholedochal blood clot. Br J Surg 1981;68:885. 14. Mosenkis BN, Brandt LJ. Bleeding causing biliary obstruction after endoscopic sphincterotomy. Am J Gastroenterol 1997;92:708-9. 15. Vagianos C, Karavias D, Dragotis C, Kalofonos H, Androulakis J. Obstructive jaundice due to intracholedochal blood clot: an unusual early presentation of primary hepatic carcinoma. Br J Clin Pract 1993; 47:222-3. 16. Van Os EC, Petersen BT. Pancreatitis secondary to percutaneous liver biopsy-associated hemobilia. Am J Gastroenterol 1996;91:577-80. 17. Jornod P, Wiesel PH, Pescatore P, Govers JJ. Hemobilia, a rare cause of acute pancreatitis after percutaneous liver biopsy: diagnosis and treatment by endoscopic retrograde cholangiopancreatography. Am J Gastroenterol 1999;94:3051-4. 18. Stewart L, Robinson TN, Lee CM, Liu K, Whang K, Way LW. Right hepatic artery injury associated with laparoscopic bile duct injury: incidence, mechanism, and consequences. J Gastrointest Surg 2004;8: 523-30; discussion 530-1. 19. Yelle JD, Fairfull-Smith R, Rasui P, Lorimer JW. Hemobilia complicating elective laparoscopic cholecystectomy: a case report. Can J Surg 1996; 39:240-2. 20. Sandblom P. Iatrogenic hemobilia. Am J Surg 1986;151:754-8.