Ulcerative Colitis: Dörffel Y

Swidsinski A, Loening-Baucke V, Bengmark S, Lochs H, Dörffel Y. · Humboldt University, Charité Hospital, CCM, Laboratory for Molecular Genetics, Polymicrobial Infections and Bacterial Biofilms, 10098 Berlin, Germany. · Inflamm Bowel Dis. · Pubmed #17206639 links to  free full text

Abstract: BACKGROUND: The impact of azathioprine and 5-aminosalicylic acid (5-ASA) on the innate immunity and mucosal flora is unknown. The study investigated the influence of IBD treatment on the concentrations and spatial organization of mucosal bacteria using fluorescence in situ hybridization with 16s r-RNA targeting probes. METHODS: We prospectively investigated colonoscopic biopsies from five groups of 20 subjects each: patients with ulcerative or indeterminate colitis treated with azathioprine (group 1), azathioprine and 5-ASA (group 2), 5-ASA (group 3), untreated IBD (group 4), and healthy controls. RESULTS: The elevated numbers of leukocytes in mucus of IBD patients were reduced nearly to norm in patients treated with azathioprine alone. In contrast, 5-ASA therapy had no influence on mucus leukocyte migration and was associated with the lowest concentrations of mucosal bacteria of all IBD groups. The suppressed migration of leukocytes in azathioprine-treated patients was accompanied by a 28-fold higher concentration of mucosal bacteria when compared with the 5-ASA group or a 1000-fold increase when compared with healthy controls. The percent of the epithelial surface covered with adherent bacteria (P < 0.001) and the amenability of mucosal bacteria (P = 0.01) were also significantly increased in the azathioprine-treated group compared with all other IBD groups. The patients receiving both 5-ASA and azathioprine did not differ statistically from untreated IBD patients either in mucus leukocyte migration or in bacterial concentrations. CONCLUSIONS: Azathioprine and 5-ASA induce opposite effects on the mucus barrier. Concomitant therapy of 5-ASA and azathioprine mutually neutralizes the effects of both on the mucosal flora and the barrier function.

Swidsinski A, Loening-Baucke V, Theissig F, Engelhardt H, Bengmark S, Koch S, Lochs H, Dörffel Y. · Humboldt University, Charité, CCM, 10098 Berlin, Germany. · Gut. · Pubmed #16908512 No free full text.

Abstract: AIM: To study the role of mucus in the spatial separation of intestinal bacteria from mucosa. PATIENTS AND METHODS: Mucus barrier characteristics were evaluated using histological material obtained by biopsy from purged colon, colon prepared with enema and material from untreated appendices fixed with non-aqueous Carnoy solution. Bacteria were evaluated using fluorescence in situ hybridization, with bacterial 16S RNA probes and related to the periodic acid Schiff alcian blue stain. Biopsies from controls (n = 20), patients with self-limiting colitis (SLC; n = 20), ulcerative colitis (n = 20) and 60 randomly selected appendices were investigated. RESULTS: The mucosal surface beneath the mucus layer was free of bacteria in > or =80% of the normal appendices and biopsies from controls. The thickness of the mucus layer and its spread decreased with increasing severity of the inflammation; the epithelial surface showed bacterial adherence, epithelial tissue defects and deep mucosal infiltration with bacteria and leucocytes. Bacteria and leucocytes were found within mucus in all biopsy specimens from patients with ulcerative colitis, SLC, and acute appendicitis. The concentration of bacteria within mucus was inversely correlated to the numbers of leucocytes. CONCLUSIONS: The large bowel mucus layer effectively prevents contact between the highly concentrated luminal bacteria and the epithelial cells in all parts of the normal colon. Colonic inflammation is always accompanied by breaks in the mucus barrier. Although the inflammatory response gradually reduces the number of bacteria in mucus and faeces, the inflammation itself is not capable of preventing bacterial migration, adherence to and invasion of the mucosa.