Gut Microbiota Contribute to the Regulation of Cellular Inflammation in Irritable Bowel Syndrome and Anxiety/Depression: A review of current literature.

Gut microbiota are mutualistic microorganisms living within the intestinal tract. Common genera include Bacteroides, Prevotella, Ruminococcus and Lactobacillus. These bacteria aid in digestion and been found to confer many regulatory and protective functions upon the host (Dinan et. al. 2012). Some of these functions operate through the so-called gut-brain axis, a term which references the interconnectivity of the enteric nervous system, central nervous system, and intestinal microbiota (Rhee et. al. 2009). This incidental neural influence exerted by gut bacteria can have many effects throughout the body, including regulating the production of stress hormones by the hypothalamus- pituitary-adrenal axis (HPA) (Collins et. al 2009). Balancing the gut microbiota is now being explored as a treatment for both irritable bowel syndrome (IBS) and anxiety/depression, both of which implicate the HPA as playing a key role in their pathology. Furthermore, a balanced microbiota has been strongly linked to a generalized anti-inflammatory effect, and this may also contribute to the ameliorating effect a balanced gut microbiome has on the aforementioned conditions. This synopsis will present some of the recent advances to our understanding of how the gut microbiota influence the release of stress hormones, and show that dysbiosis can exacerbate existing levels of inflammatory factors through altering the HPA axis