Ulcerative Colitis: Heller F

Heller F, Duchmann R. · Medizinische Klinik I, Universitätsklinikum Benjamin Franklin, FU-Berlin, Hindenburgdamm 30, D-12200 Berlin, Germany. · Int J Med Microbiol. · Pubmed #12755368 No free full text.

Abstract: The normal intestinal flora and the mucosal immune system exist in close spatial proximity. A normal structure and function of both very complex systems is required for health and develops in a constant and interactive process. An abnormal host response to the normal intestinal flora leads to chronic intestinal inflammation. Probiotic bacteria may modulate the intestinal flora and the mucosal immune response and are an effective therapy for remission maintenance of ulcerative colitis and pouchitis.

Bojarski C, Günther U, Rieger K, Heller F, Loddenkemper C, Grünbaum M, Uharek L, Zeitz M, Hoffmann JC. · Medical Department I Gastroenterology, Infectious Diseases, Rheumatology, Charité Campus Benjamin Franklin, Berlin, Germany. · Endoscopy. · Pubmed #19418398 No free full text.

Abstract: BACKGROUND AND STUDY AIMS: Conventional histology with hematoxylin and eosin (H&E) staining is the accepted standard for diagnosing acute intestinal graft-versus-host disease (GvHD). Confocal endomicroscopy (CEM) is a noninvasive method that allows in vivo histology to be performed during endoscopy. The aim of this study was to evaluate CEM for the diagnosis of acute intestinal GvHD. PATIENTS AND METHODS: This observational pilot study conducted between September 2006 and August 2008 included patients with acute diarrhea after stem cell transplantation, infectious diarrhea, or active ulcerative colitis. CEM (EC-3870CIFK, Pentax, Tokyo, Japan) was performed after intravenous injection of fluorescein 10% and topical application of acriflavine 0.05%. RESULTS: A total of 35 patients with acute diarrhea after stem cell transplantation were examined. In 16 patients, CEM and histology showed no evidence of GvHD. In 14/19 patients with histologically confirmed GvHD, the diagnosis could already be established by CEM during ongoing endoscopy. In GvHD grade IV, near complete destruction of the colonic crypts ("flat mucosa") was visible. Control patients with infectious colitis (N = 15) or ulcerative colitis (N = 15) displayed inflammatory changes but no evidence of GvHD. Altogether, sensitivity of CEM was 74% and specificity was 100 %. CONCLUSIONS: CEM improves rapid diagnosis of acute intestinal GvHD with high accuracy while performing endoscopy. Platelet transfusions and unnecessary biopsy acquisition can be avoided once acute intestinal GvHD has been diagnosed in vivo.

Heller F, Fromm A, Gitter AH, Mankertz J, Schulzke JD. · Department of Gastroenterology, Infectious Diseases and Rheumatology, Charité, Campus Benjamin Franklin, Berlin, Germany. · Mucosal Immunol. · Pubmed #19079233 No free full text.

Abstract: In ulcerative colitis, the T helper type 2 proinflammatory cytokine Interleukin-13 (IL-13) contributes as effector cytokine to the epithelial changes associated with disturbed epithelial barrier function. This study aimed to investigate the underlying mechanisms in a colonic epithelial cell culture model. For studying these epithelial features in response to proinflammatory cytokines epithelial apoptosis was investigated by TdT-mediated X-dUTP nick end labeling (TUNEL) staining in HT-29/B6 cell monolayers. In contrast to interferon-gamma, IL-13 significantly upregulated the apoptotic rate of cells, which was intensified by simultaneous exposure to tumor necrosis factor-alpha. That this has a direct functional influence on epithelial barrier was shown by the caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp, which inhibited IL-13 induced apoptosis induction and concomitantly reversed the decrease in epithelial resistance by approximately 50%. Direct evidence for apoptotic rosettes at corresponding sites of barrier defects in the epithelium was obtained by conductance scanning. In addition, the pore-forming tight junction protein claudin-2 was found to be upregulated at protein and mRNA level. In conclusion, IL-13 disturbs intestinal barrier function through mechanisms including apoptosis induction and alteration of tight junction protein composition.

Schulzke JD, Bojarski C, Zeissig S, Heller F, Gitter AH, Fromm M. · Medizinische Klinik I, Department of Gastroenterology, Infectious Diseases and Rheumatology, Charité, Campus Benjamin Franklin, 12200 Berlin, Germany. · Ann N Y Acad Sci. · Pubmed #17057208 No free full text.

Abstract: Epithelial barrier function is determined by trans- and paracellular permeabilities, the latter of which is mainly influenced by tight junctions (TJs) and apoptotic leaks within the epithelium. The present article aims to present experimental evidence for a functional role of epithelial apoptoses by means of cell culture models as well as in tissues from patients with inflammatory bowel disease. It is shown that epithelial apoptoses are sites of elevated conductance within the intestinal epithelium and that proinflammatory cytokines like TNF-alpha upregulate both the apoptotic rate and single apoptotic conductivity, making cytokine-induced apoptosis functionally far more relevant than is spontaneous apoptosis. In ulcerative colitis and Crohn's disease (CD), but not in collagenous colitis, apoptotic rates are increased to about 5%, in mild-to-moderately inflamed colon specimens, where as the control apoptotic rate is about 2%. Thus, epithelial apoptoses lead to a loss of ions and water into the intestinal lumen, causing leak flux diarrhea and enabling small antigens of <4,000 Da in the intestinal lumen to enter the intestinal mucosa, thereby perpetuating inflammatory responses. In addition to TNF-alpha, interleukin (IL)-13 is an important inductor of epithelial apoptosis in Th2 immune responses. Therapeutically,TNF-alpha-antibodies (infliximab) can restore barrier function in Crohn's disease by downregulating epithelial apoptoses, while epithelial TJs are unaffected.

Fuss IJ, Becker C, Yang Z, Groden C, Hornung RL, Heller F, Neurath MF, Strober W, Mannon PJ. · Mucosal Immunity Section, Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 , USA. · Inflamm Bowel Dis. · Pubmed #16374252 No free full text.

Abstract: BACKGROUND: Interleukin (IL)-12p70 and IL-23 are key T helper-1 (TH1) cytokines that drive the inflammation seen in numerous models of intestinal inflammation. These molecules contain an identical p40 chain that is bound to a p35 chain in IL-12 and a p19 chain in IL-23, making both potentially susceptible to modulation by an anti-IL-12p40 monoclonal antibody (mAb). METHODS: In the present study, we sought to determine whether active inflammation in Crohn's disease (CD) is associated with the increased synthesis of both of these cytokines and whether patients treated with an anti-IL-12p40 mAb down-regulate IL-23 as well as IL-12p70 as previous reported. RESULTS: To this end we initially determined that IL-12p70 secretion by control and CD antigen-presenting cells (macrophages) in lamina propria mononuclear populations is optimized by stimulation with CD40L and interferon-gamma. In subsequent studies using these stimulation conditions we found that patients with CD manifested both increased IL-12p70 and IL-23 secretion before anti-IL-12p40 mAb treatment and normal levels of secretion of these cytokines following cessation of treatment. Antigen-presenting cells in lamina propria mononuclear cells from ulcerative colitis patients, in contrast, produced only baseline levels of IL-23. Finally, we found that IL-23-induced T cell production of IL-17 and IL-6 are also greatly reduced after antibody treatment. The latter data are parallel to those from previous studies showing that anti-IL-12p40 down-regulates IFN-gamma and tumor necrosis factor-alpha secretion. CONCLUSIONS: We conclude that CD but not ulcerative colitis is associated with high levels of both IL-12p70 and IL-23 secretion as well as the secretion of downstream effector cytokines, and that this cytokine production is down-regulated following administration of IL-12p40 mAb.

Heller F, Florian P, Bojarski C, Richter J, Christ M, Hillenbrand B, Mankertz J, Gitter AH, Bürgel N, Fromm M, Zeitz M, Fuss I, Strober W, Schulzke JD. · Department of Gastroenterology, Charité, Campus Benjamin Franklin, Berlin, Germany. · Gastroenterology. · Pubmed #16083712 No free full text.

Abstract: BACKGROUND & AIMS: Ulcerative colitis (UC) is characterized by a Th2 immune response with inflammation and epithelial barrier dysfunction. So far, Th2 cytokines have not been shown to directly influence epithelial barrier function. METHODS: Lamina propria mononuclear cells (LPMCs) were stimulated and interleukin (IL)-13 was measured by enzyme-linked immunosorbent assay. Functional IL-13 and IL-4 effects were studied on HT-29/B6 colonic epithelial cells in Ussing chambers and by conductance scanning. Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assays. IL-13/IL-4 receptors were analyzed by reverse-transcription polymerase chain reaction and immunofluorescence. Western blotting combined with immunofluorescence was used to detect tight junction proteins. Furthermore, restitution velocity was measured. Finally, mucosal biopsy specimens from patients with UC were compared with cultured cells for these features. RESULTS: LPMCs from patients with UC produced large amounts of IL-13 (985 +/- 73 pg/mL), much more than from controls or patients with Crohn's disease. IL-13Ralpha1 and IL-4Ralpha receptors were present in HT-29/B6 cells and colonic epithelial cells of control patients and patients with UC. IL-13 had a dose-dependent effect on transepithelial resistance of HT-29/B6 monolayers (reduction to 60% +/- 4%), whereas IL-4 had no effect. This was due to an increased number of apoptotic cells (5.6-fold +/- 0.9-fold) and an increased expression of the pore-forming tight junction protein claudin-2 to 295% +/- 37%, both of which contributed equally. Finally, epithelial restitution velocity decreased from 15.1 +/- 0.6 to 10.6 +/- 0.5 microm/h after treatment with IL-13. Parallel changes were observed in human samples, with an increase in claudin-2 expression to 956% +/- 252%. CONCLUSIONS: IL-13 was identified as an important effector cytokine in UC that impairs epithelial barrier function by affecting epithelial apoptosis, tight junctions, and restitution velocity.

Fuss IJ, Heller F, Boirivant M, Leon F, Yoshida M, Fichtner-Feigl S, Yang Z, Exley M, Kitani A, Blumberg RS, Mannon P, Strober W. · Mucosal Immunity Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda Maryland 20892, USA. · J Clin Invest. · Pubmed #15146247 links to  free full text

Abstract: While Crohn disease (CD) has been clearly identified as a Th1 inflammation, the immunopathogenesis of its counterpart inflammatory bowel disease, ulcerative colitis (UC), remains enigmatic. Here we show that lamina propria T (LPT) cells from UC patients produce significantly greater amounts of IL-13 (and IL-5) than control cells and little IFN-gamma, whereas comparable cells from CD patients produce large amounts of IFN-gamma and small amounts of IL-13. We then show that stimulation of UC LPT cells bearing an NK marker (CD161) with anti-CD2/anti-CD28 or with B cells expressing transfected CD1d induces substantial IL-13 production. While this provided firm evidence that the IL-13-producing cell is an NK T (NKT) cell, it became clear that this cell does not express invariant NKT cell receptors characteristic of most NKT cells since there was no increase in cells binding alpha-galactosylceramide-loaded tetramers, and alpha-galactosylceramide did not induce IL-13 secretion. Finally, we show that both human NKT cell lines as well as UC CD161(+) LPT cells are cytotoxic for HT-29 epithelial cells and that this cytotoxicity is augmented by IL-13. These studies show that UC is associated with an atypical Th2 response mediated by nonclassical NKT cells producing IL-13 and having cytotoxic potential for epithelial cells.

Heller F, Fuss IJ, Nieuwenhuis EE, Blumberg RS, Strober W. · Mucosal Immunity Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. · Immunity. · Pubmed #12433369 No free full text.

Abstract: Oxazolone colitis (OC) is an experimental colitis that has a histologic resemblance to human ulcerative colitis. Here we show that IL-13 production is a significant pathologic factor in OC since its neutralization by IL-13Ralpha2-Fc administration prevents colitis. We further show that OC is mediated by NK-T cells since it can be induced neither in mice depleted of NK-T cells nor in mice that cannot present antigen to NK-T cells and mice lacking an NK-T cell-associated TCR. Finally, we show that NK-T cells are the source of the IL-13, since they produce IL-13 upon stimulation by alpha-galactosylceramide, an NK-T cell-specific antigen. These data thus describe a cellular mechanism underlying an experimental colitis that may explain the pathogenesis of ulcerative colitis.