Functional Genomics of Human Obesity Related to Cardiometabolic Diseases

Composed of about 10 trillion cells, the human body is host to 100 trillion bacteria which constitute an extremely rich and diverse flora. From a genetic point of view there is 500,000 bacterial genes on average compared to 23,000 genes in the human genome. Indeed, a human being is the result of a mutualistic association, stemming from a co-evolution, whom balance is essential to maintaining the health and well-being. The intestinal flora is now seen as a full organ linking (external) environmental factors and biology of the organism (the host). It provides essential functions throughout life. An imbalance of the intestinal flora or dysbiosis has been demonstrated in a variety of human diseases, whether metabolic, cardiovascular or immuno-inflammatory. These observations have been made in particular through the development, in recent years, of tools for the study of the metagenome allowing the sequencing of bacterial genes from the gut microbiome. A factor very frequently found is the loss of bacterial diversity. Although the loss of diversity is typically associated with taking antibiotics, it is also found in other diseases such as cystic fibrosis, intestinal disorders, and more recently in metabolic diseases such as diabetes and obesity. Recently, our team has helped to show that obese people with a loss of bacterial diversity had more risk factors (dyslipidemia, low-grade inflammation) and improved less these risk factors with a restrictive but rich in fibers diet. This presentation will review the recent discoveries in the field by taking the example of metabolic diseases.