How Decisive Are Commensal Bacteria

Indigenous gut bacteria play a central role in the extended hygiene hypothesis. Thus, the intestinal microbiota of young children in Sweden was found to contain a relatively large number of Clostridium spp., whereas high levels of Lactobacillus spp. and Eubacterium spp. were detected in 234 an age-matched population from Estonia this difference might contribute to the lower incidence of allergy in the Baltic countries compared with Scandinavia 235 . A Finnish study likewise reported that...

Nutrition and Diet

Considerable efforts have been made in the search for nutritional factors related to, and maybe even responsible for the development of IBD. The methodology of this research has been hampered by the problems of confounding factors and the fact that many patients will change their nutritional habits as a consequence of the disease. There are many studies in small cohorts of patients, who claim that intake of certain diet constituents like fat, refined sugar, fruits, vegetables, and fiber affect...

Inductive Gut Associated Lymphoid Tissue Structures

Intestinal immune cells are located in three compartments GALT, the mucosal lamina propria, and the surface epithelium (Fig. 3.2). GALT comprises Peyer's patches, the appendix, and numerous ILFs 2, 6, 30 . These organized lymphoid structures represent inductive sites for intestinal immune responses, while the lamina propria and epithelial compartment principally constitute effector sites but may nevertheless contribute to retention, proliferation, and differentiation of immune cells 31 . Fig....

Mechanisms Promoting Homeostasis

Crohn Disease Mechanism

Numerous genes regulate both the innate and adaptive arms of the immune system. Human immu-nogenetics has evolved to identify danger under the pressure of a dirty environment, even long beyond the hunting-gathering period. In this evolutionary process the intestinal immune system has generated its two adaptive anti-inflammatory strategies immune exclusion performed by SIgA to control surface colonization of microorganisms and inhibit mucosal penetration of potentially dangerous agents and oral...

The Epithelial Barrier Function

Although so-called gut closure normally occurs in humans mainly before birth, the mucosal barrier may be inadequate up to 2 years of age the mechanisms involved remain poorly defined 73 , but the development of secretory immunity is probably one decisive variable. Importantly in this context, pIgR-deficient knockout mice that lack SIgA and SIgM exhibit aberrant mucosal leakiness 74 and have increased uptake of food proteins and commensal bacteria 75 . A thick virtually microbe-devoid inner...

Micronutrients and Microparticles

Both in food and water supply, metals and minerals, as well as other microparticles, are abundant, and as such more common as part of pollution in industrialized areas. These particles may act in different ways with the immune system, causing primary or secondary effects. It has been suggested that exposure to xenobiotic-like metals may induce immune responses in autoimmune diseases. Such reactions have been related to effects of mercury 105 , cobalt, zirconium, beryllium, silver, and aluminum...

Contents

1 The Genetics of Inflammatory Bowel 3 2 Environmental Factors in the Epidemiology of Inflammatory Bowel Disease 17 3 The Intestinal Immune System in 41 4 Understanding the Epithelial Barrier in Inflammatory Bowel Disease 75 Emily M. Bradford, Emily S. Turner, and Jerrold R. Turner 5 Intestinal Microbiology and Ecology in Inflammatory Bowel Disease 85 6 Microbial Recognition and Pathogen-Associated Molecular Pattern Kenya Honda, Koji Atarashi, and Junko Nishio 7 Inflammasomes in Inflammatory...