Microbial Factors in the Pathogenesis of IBD

Effect of Saccharomyces cerevisiae strain UFMG A-905 in experimental model of inflammatory bowel disease

In the present study, the protective potential of Saccharomyces cerevisiae strain UFMG A-905 was evaluated in a murine model of acute ulcerative colitis (UC). Six groups of Balb/c mice were used: not treated with yeast and not challenged with dextran sulphate sodium (DSS) (control); treated with S. cerevisiae UFMG A-905 (905); treated with the non-probiotic S. cerevisiae W303 (W303); challenged with DSS (DSS); treated with S. cerevisiae UFMG A-905 and challenged with DSS (905 + DSS); and treated with S. cerevisiae W303 and challenged with DSS (W303 + DSS). Seven days after induction of UC, mice were euthanised to remove colon for enzymatic, immunological, and histopathological analysis. In vivo intestinal permeability was also evaluated. An improvement of clinical manifestations of experimental UC was observed only in mice of the 905 + DSS group when compared to animals from DSS and W303 + DSS groups. This observation was confirmed by histological and morphometrical data and determination of myeloperoxidase and eosinophil peroxidase activities, intestinal permeability and some pro-inflammatory cytokines. S. cerevisiae UFMG A-905 showed to be a potential alternative treatment for UC when used in an experimental animal model of the disease.

[The prevalence of Helicobacter pylori infection in Korean patients with inflammatory bowel disease, a multicenter study]

BACKGROUND/AIMS

The prevalence of Helicobacter pylori (H. pylori) infection has been reported to be lower in individuals with inflammatory bowel disease (IBD) in some Western countries. We investigated H. pylori infection in Korean patients with IBD and any possible associations of H. pylori infection with drug therapy for IBD and the phenotype of Crohns disease (CD).

METHODS

We studied 316 unselected patients with IBD, including 169 ulcerative colitis (UC) patients and 147 with CD, and the control group consisted of 316 age- and gender-matched healthy people who received a comprehensive medical examination for a regular checkup purpose. Infection rates of H. pylori as detected by the urea breath test were compared between the IBD patients and the controls.

RESULTS

A statistically significant difference in H. pylori infection rate was noticed between the IBD patients (25.3%) and the controls (52.5%; p<0.001), and between UC (32.0%) and CD patients (17.7%; p=0.04). Among the IBD patients, the age group of <60 and individuals with a history of taking metronidazole (13.0%; p=0.038) or ciprofloxacin (6.7%; p=0.001) were found to have a meaningfully lower infection rate, but those who did not take antibiotics still showed H. pylori infection rate significantly lower than the controls (CD 22.0% vs. UC 33.8% vs. Control 52.5%, p<0.001). With an exception of age, phenotypic characteristics showed no significant relations with H. pylori infection rate in CD patients.

CONCLUSIONS

Korean patients with IBD, particularly CD, were found to have a significantly lower H. pylori infection rate than the controls. This association was more evident in those <60 years old, which suggested that H. pylori infection might be deemed to lower possible risks of IBD in younger adults.

Inhibitory effects of fermented brown rice on induction of acute colitis by dextran sulfate sodium in rats

Although the pathogenic mechanisms of inflammatory bowel diseases are not fully understood, colonic microbiota may affect the induction of colonic inflammation, and some probiotics and prebiotics have been reported to suppress colitis. The inhibitory effects of brown rice fermented by Aspergillus oryzae (FBRA), a fiber-rich food, on the induction of acute colitis by dextran sulfate sodium (DSS) were examined. Feeding a 5% and 10% FBRA-containing diet significantly decreased the ulcer and erosion area in the rat colon stained with Alcian blue. In another experiment, 10% FBRA feeding decreased the ulcer index (percentage of the total length of ulcers in the full length of the colon) and colitis score, which were determined by macroscopic observation. It also decreased myeloperoxidase activity in the colonic mucosa. Viable cell numbers of Lactobacillus in the feces decreased after DSS administration and was reversely correlated with severity of colitis, while the cell number of Enterobacteriaceae increased after DSS treatment and was positively correlated with colitis severity. These results indicate that FBRA has a suppressive effect on the induction of colitis by DSS and suggest FBRA-mediated modification of colonic microbiota.

Inflammatory bowel disease pathogenesis: therapeutic implications

The pathogenesis of inflammatory bowel disease (IBD) is complex, involving environmental, genetic, microbial, and immune factors. Therefore, treatment should target components that either predispose to or mediate the chronic inflammatory response of IBD. At the moment it is assumed that all components are necessary to have the typical manifestations of IBD but, in reality, it is unclear to what extent each factor contributes to the disease process, and whether some are more important than others. In addition, some factors are not practical targets; for example, environmental factors are poorly defined, too numerous, and require changes that cannot be implemented by the physician or the patient alone. The same is true for genetic factors that are still not amenable to therapeutic manipulations for technical and ethical reasons. This leaves microbial and immune factors as the two categories that can be selected for therapeutic intervention and where all current treatments are focused. The commensal gut flora can be qualitatively or quantitatively modified with antibiotics, probiotics, or diet, and a better characterization of enteric bacteria strains should help greatly in developing more effective therapies. Most current drugs are focused on inhibiting pro-inflammatory molecules produced by immune cells, including biological agents that block specific cytokines such as tumor necrosis factor-alpha. It is anticipated that combination therapies targeting multiple pathogenic components will prove more effective than those blocking single components of IBD pathogenesis.