Prospective Uses of Genetically Engineered Lactic Acid Bacteria for the Prevention of Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is a term used to describe a group of intestinal disorders in which inflammation is a major feature. Although rare forms of IBD exist, these diseases normally pertain to ulcerative colitis (UC) (Head & Jurenka, 2003) and Crohn’s disease (CD) (Baumgart & Sandborn, 2007). There is evidence that these do not represent distinct conditions but rather are the same disease with shared etiological factors (Price, 1992); however, clinical manifestations (such as the exact location of the pathology or the affected individual’s immunological and constitutional endowment) are distinctive between both. Despite many years of study, the exact etiology and pathogenesis of these disorders remain unclear but great advances have been made using experimental animal models and have provided insights into the complex, multi-factorial processes and mechanisms that can result in chronic intestinal inflammation (Elson & Weaver, 2003). The aim of this chapter is to present an overview of the current expanding knowledge of the mechanisms by which lactic acid bacteria and other probiotic microorganisms participate in the prevention and treatment of IBD and how genetic engineering techniques can be used to improve their effectiveness or create novel therapeutic strains. In the following sections, the mechanisms by which these beneficial microorganisms exert their therapeutic effects, which include changes in the gut microbiota, stimulation of the host immune responses, enhancement of intestinal barrier function and reduction of the oxidative stress due to their antioxidant properties will be discussed.