MedicalResearch.com Interview with:
Prof. Dr. Patrice D. Cani PhD,
Research Associate FRS-FNRS
Louvain Drug Research Instiute, Metabolism and Nutrition
WELBIO, Walloon Excellence in Life sciences and BIOtechnology
NeuroMicrobiota lab, European Associated Laboratory (INSERM/UCL) and
Dr Amandine Everard
Université Catholique de Louvain, Louvain Drug Research Institute, WELBIO (Walloon Excellence in Life sciences and BIOtechnology), Metabolism and Nutrition Research Group, Brussels, Belgium
Medical Research: What is the background for this study? What are the main findings?
Response: Our intestine harbors more than 100 trillions of bacteria. This huge number of bacteria permanently interacts with our own human cells. Among the systems involved in this crosstalk, the immune system plays a key role in these interactions.
We previously showed that specific gut bacteria are able to control energy metabolism, harmful inflammation associated with obesity, body weight gain and
type-2 diabetes. However mechanisms involved these effects of gut bacteria on the host during obesity and type-2 diabetes were poorly understood.
We identify the essential role of the intestinal immune system in the onset of obesity and type-2 diabetes both induced by a high dose of fat in the diet. This discovery highlights an unexpected mechanism for the control of energy metabolism during obesity and type-2 diabetes.
We demonstrate for the first time that the inactivation of a part of the intestine immune system (more specifically the protein MyD88), which is overstimulated by a diet rich in fat, allows to induce weight-loss and to reduce type-2 diabetes associated with obesity.
When we tune the immune system by disabling the protein MyD88 specifically in cells covering the intestine, we are able to limit the
adipose tissue development induced by the diet rich in fat, to slow down diabetes, to reduce harmful inflammation associated with obesity, to reinforce gut barrier function assumed by our intestine to avoid the inappropriate translocations of bacteria compounds from our intestine in our body.
We reveal various mechanisms explaining the partial protection against obesity induced by the inactivation of this protein of the immune system. Among them, we point out that mice that do not have this protein of the immune system (i.e. MyD88) in their intestine are partially protected against obesity because they spend more energy than other obese mice.
Moreover, our study shows that this protein of the immune system is able to shape the composition of the gut microbiota residing in our intestine under a high-fat diet. These changes observed in mice deleted for this protein also explain their protection against obesity because when we transfer intestinal bacteria of these mice into other mice that are axenic (without flora), these latest mice are also partially protected against obesity.
In conclusions, our studies published in the scientific journal
Nature Communications, demonstrated that during consumption of fat food, the intestinal immune system plays an important role in fat storage regulation in the body and is capable to modify the composition of intestinal bacteria (including some which are still unidentified), confirm the implication of intestinal bacteria in the onset of obesity.
(more…)