Editorial [Hot Topic: The Human Microbiome - A Therapeutic Target for Prevention and Treatment of Chronic Disease (Executive Editor: Kieran Tuohy)]

Each one of us exists in close symbiosis with a diverse and unique collection of microorganisms comprising the human microbiome. The colonic microbiota, representing the greater part of this microbiome, differs in species composition and relative population levels between individuals imparting great metabolic variability in the way our bodies respond to biologically active compounds which escape digestion or are shunted into the colon via bile secretions. Our microbial partners have co-evolved alongside humankind over the millennia, and are intimately involved in human health and disease. Recently there has been an upsurge of interest in gut microbiology, driven in part by ground breaking research employing metabonomic and metagenomic technologies which are providing novel and dramatic insights into the functioning of the gut microbiota, its interactions with human diet and xenobiotic metabolism, and in its interactions with host physiology and disease states. This issue of Current Pharmaceutical Design comprises a series of reviews by leading opinion formers, which present current understanding of the human microbiome, its role in chronic human disease, and which identify the gut microbiota as a putative therapeutic target discussing dietary means of modulating its activities. Saulnier et al. [1] describe in great detail the dichotomous nature of the human gut microbiota, at once being beneficial and essential for human wellbeing, as well as possessing the capacity to cause human disease. The authors go on to discuss how through dietary supplementation using probiotics, prebiotics and synbiotics, this balance between health promoting and deleterious activities may be modulated to improve host health. Putting probiotics, prebiotics and synbiotics into an historical and current market perspective, the authors provide a useful introduction to the proposed mechanisms underpinning these microbiota modulatory dietary tools and set the scene for concepts re-visited by others in this current issue. The authors also present a summary of culture independent molecular microbiological tools now being used to study the gut microbiota. This theme is taken up and expanded in Tuohy et al. [2], where we describe the recent application of metagenomics and metabonomics to study the human gut microbiota. Here, the notion of our co-evolved gut microbiota and its interaction with human diets past and present is discussed against the back-drop of high resolution “-omics” based techniques and the challenges facing gut microbial ecology in assigning biological function to novel gut bacteria, the vast majority of which resist cultivation under laboratory conditions.