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ABSTRACT: Various commensal enteric and pathogenic bacteria may be involved in the pathogenesis of inflammatory bowel diseases (IBDs), a chronic condition with a pathogenic background that involves both immunogenetic and environmental factors. IBDs comprising of Crohn's disease, and ulcerative colitis, and pauchitis are chronic inflammatory conditions, and known for causing disturbed homeostatic balance among the intestinal immune compartment, gut epithelium and microbiome. An increasing trend of IBDs in incidence, prevalence, and severity has been reported during recent years. Probiotic strains have been reported to manage the IBDs and related pathologies, and hence are current hot topics of research for their potential to manage metabolic diseases as well as various immunopathologies. However, the probiotics industry will need to undergo a transformation, with increased focus on stringent manufacturing guidelines and high-quality clinical trials. This article reviews the present state of art of role of probiotic bacteria in reducing inflammation and strengthening the host immune system with reference to the management of IBDs. We infer that t healthcare will move beyond its prevailing focus on human physiology, and embrace the superorganism as a paradigm to understand and ameliorate IBDs.
KEY WORDS: Gut Microbiome, Immunomodulation, Inflammatory bowel diseases, Probiotics.
INTRODUCTION
The mammalian gut contains 300-500 different bacterial species, and overall concentration of microbial species inhabiting the human gastrointestinal (GI) tract may reach 1011-1012 cells per gram of luminal contents (Guarner and Malagelada, 2003). Under normal circumstances, majority of the GI symbionts are protective and some are neutral, but a few can turn pathogenic if gut physiology become abrupt (Sartor, 2004). This dynamic community of GI microbiome plays a critical role in maintaining intestinal health serving metabolic, digestive, trophic as well as protective functions (Guarner and Malagelada 2003). Probiotics when administered or ingested in specific quantities, exert beneficial physiologic and therapeutic health benefits besides their normal metabolic properties (Sartor 2004; Fioramonti et al., 2003). Examples of probiotic bacteria demonstrated to have beneficial effects include lactic acid bacteria (LAB), Bifidobacterium sp., Escherichia coli Nissle 1917, Streptococcus thermophilus and a non-pathogenic yeast, Saccharomyces boulardii etc. (Fioramonti et al., 2003; Kumar et al., 2009; 2010; 2011; 2012a, b, c; Nagpal et al., 2007; 2010; 2012a, b, c; Nagpal and Kaur, 2011). Potential mechanisms of probiotic action (Fig. 1) include competitive interactions,...