A common core microbiota between obese individuals and their lean relatives? Evaluation of the predisposition to obesity on the basis of the fecal microflora profile

Obesity represents a crucial social problem in developed countries as a cause of multiple metabolic abnormalities. The exact etiology of this multifactorial disease is still unknown. The impact of dietary habits and lifestyle is currently under investigation but the role of other predisposing factors, such as genetic determinants and familial history, needs still to be elucidated. Significant alterations in the composition of the intestinal microbiota have been recently identified in obese mice, suggesting an involvement of gut microbes in obesity. In humans, obese subjects are supposed to have a more efficient flora in energy extraction from food, due to the detection of quantitative differences in the major bacterial groups in obese subjects compared to lean ones. Despite these observations, the homologies in gut microbiota between obese adults and their lean relatives have never been investigated in details. Few reports about the detection of common microbial profiles between members of the same family have been published in the past but only one recent scientific article, investigating the presence of a common core microbiota between obese and lean twins, correlates genetic background and gut microflora as significant variables in obesity. The hypothesis suggested herein is that the identification of a familial-specific core microbiota could be precious in order to identify key-bacterial groups to be used as biomarkers for the evaluation of predisposition to obesity.