La détection centrale des lipides et la régulation du comportement alimentaire : implication dans l'obésité

The modern abundance of energy-rich foods combined with a shift to more sedentary lifestyles has led to a thermodynamic imbalance in which excessive caloric intake and reduced energy expenditure account for the prevalence of obesity. In particular, exposure to lipid-rich diet is thought to promote metabolic alteration in peripheral tissue associated with obesity-related diseases. The regulation of energy balance depends on the ability of the brain to provide an adaptive response to change in circulating factors of hunger and satiety. The hypothalamus and the brain stem are particularly regarded as key integrative structure but, aside from the energetic control, feeding behavior is also modulated by sensory inputs, such as tastes and odors, as well as by affective or emotional states, which regulate the hedonic aspect of food intake. This aspect of food intake is closely tied to the release of the neurotransmitter dopamine by the reward system, which is stimulated by calorie-dense foods as well as by most other objects of desire. Interestingly, these structures, involved in the control of food intake, express several enzymes implicated in the processing of lipids and the recent literature provide growing evidence that nutritional lipids within discrete brain regions can function as sensor of nutrient availability and directly control the hedonic and the energetic aspect of feeding.