Abstract
White-to-brown adipose tissue remodeling (browning) in response to different stimuli constitutes an active research area for obesity treatment. The emergence in traditional white adipose tissue (WAT) depots of multilocular adipocytes that express uncoupling protein 1 (UCP1) and resemble brown adipocytes, the so called 'brite' adipocytes, could contribute to increased energy expenditure. In rodents, obesogenic stimuli such as the intake of hyperlipidic diets can increase brown adipose tissue (BAT) thermogenic capacity and contribute to maintaining body weight. The aim of this study was to investigate the potential of two different hyperlipidic diets, a commercial high-fat (HF) diet and a highly palatable cafeteria (CAF) diet, to induce WAT browning.
We analyzed gene expression of a wide number of brown/brite adipocyte markers in different WAT depots, in BAT and in peripheral blood mononuclear cells (PBMCs) increasingly being used in nutrition studies as a potential source of biomarkers of physiological effects. We also performed morphological analysis of adipose tissue.
Both HF diets studied were able to increase the expression of the markers studied in WAT in a depot-specific manner, as well as in BAT; some of these changes were also reflected in PBMCs. This increased browning capacity was translated into the appearance of UCP1- and CIDE-A (cell death-inducing DFFA-like effector A)-positive brite adipocytes in retroperitoneal WAT. Administration of the CAF diet, associated with higher adiposity, produced the strongest impact on the parameters studied while its withdrawal restored basal conditions.
Acquisition of brown adipocyte features in WAT could evidence an adaptation to try to counteract increased adiposity due to the intake of HF diets. Additionally, PBMCs could constitute an interesting easily obtainable material to assess the effect of nutritional interventions on browning capacity.