Influência do excesso de frutose e lipídio dietéticos, isolados ou em associação, na disfunção do tecido adiposo marrom

Abstract

Obesity causes morphological and metabolic changes in brown adipocytes, causing dysfunction, known as whitening. A high-calorie diet is constantly associated with the phenomenon, but the influence of carbohydrates and lipids as energy substrates in this process has not yet been explored. This study investigated the effects of a comparable dietary excess of fat or fructose and their combination on interscapular brown adipose tissue (iBAT) whitening and markers of mitochondrial dynamics in a diet-induced obesity murine model. Male C57BL/6 adult mice were randomly assigned into four groups according to the diet: control diet (C, following AIN-93M), high-fat diet (HF, 32% energy as lard), high-fructose diet (HFRU, 32% energy as fructose) or for high-fat/high- fructose diet (HF-HFRU, 32% as lard and 32% as fructose) for 12 weeks. All diets caused insulin resistance and iBAT whitening, albeit with overweight only in the HF and HF-HFRU groups. Principal Component Analysis (PCA) indicated that the HFRU scored loaded next to inflammation markers, and the HF diet influenced more mitochondrial genes. However, iBAT whitening in all groups was associated with deficits in mitochondrial dynamics and vascularization. Similar increases in dietary saturated fat or fructose (32% as energy) and their combination caused insulin resistance and brown adipocyte dysfunction (whitening) independent of being overweight. In comparison, the PC scores of the HFRU groups were closer to the HF- HFRU group than the HF group, implying a worse outcome and highlighting the importance of limiting saturated fat and fructose intake from ultra-processed foods.