[Intestinal microbiota and novel therapeutic perspectives for the treatment of metabolic diseases].

A new organ has emerged over the course of the last century: the intestinal microbiota. It is characterized by numerous functions provided by several billions of bacteria inhabiting and living in harmony in the lumen and in the mucosal layer of the intestinal epithelium. More than 4 million genes composed by more than 1 500 species interact with each other, with the host and the environment to set up a mutualistic ecological group. A nutritional stress will modify the terms of the symbiosis between the host and the microbiota for the control of energy homeostasis. It is now thought that the pandemic of diabetes and obesity, not being due to the sole variations of our genome, would be due to changes in our metagenome: our intestinal bacteria. This organ which genomic varies on an everyday basis is inherited from our mother and the closed environment at birth. The corresponding diversity, the rapid evolution of gene expression, its influence on metabolism, as well as the very recent discovery of the existence of an tissue microbiota within the host, open new therapeutic pharmacological and nutritional opportunities as well as the identification of very accurate biomarkers constituting a personalized metagenomic identity card. Hence, individualized medicine foresees its origin within the metagenome.