Response of the Adipose tissue to Nutritional and Photoperiodic Challenges

Identificador:  TDX:2861

Handle: https://hdl.handle.net/20.500.11797/TDX2861

Autors:  Gibert Ramos, Albert

Resum:
The adipose tissue is an organ specialized in metabolism and energy storage, however, in obesity, its dysfunction is associated with several important metabolic disturbances. The increasing prevalence of obesity emphasises the importance of its prevention and treatment. The photoperiod influences many metabolic processes synchronizing the molecular clock, which, if disturbed, increases the risk of obesity. Also, according to the xenohormesis theory, fruits and vegetables signal heterotrophs about mild stresses like changes in seasons, suggesting that fruit origin should be considered in obesity preventing diets. The aim of this thesis was to evaluate whether photoperiod and consumption of fruit out of season, together with diet, could be risk factors for obesity development, focusing on the adipose tissue. Additionally, we studied whether the combination of different bioactive ingredients could improve the dysfunctional adipose tissue of obese individuals. We report that the adipose tissues of Fischer 344 rats adapt to the photoperiod, with the long day promoting fat accumulation and lipid metabolism in relation to a short day. An obesogenic diet masks some of the adaptations observed, it stimulates fat accumulation, however, the mechanism is different depending on the photoperiod. Concerning consumption of fruit out of season, orange from the southern hemisphere, with a molecular signature of a long day, stimulates fat accumulation when consumed during a short day. Furthermore, cherry consumed out of season desynchronizes the molecular clock genes and, when accompanied by an obesogenic diet, stimulates changes linked to obesity. Finally, the mix of bioactive compounds shows to be beneficial for obesity treatment, as it reduces fat accretion and stimulates an overall healthier gene expression profile in the adipose tissue. In conclusion, this work shows the importance of photoperiod and consumption of fruits out of season as risk factors for obesity, and the usefulness of a particular mix of bioactive ingredients for the treatment of obese individuals.