Brunetta 2020 J Physiol
|Brunetta HS, Politis-Barber V, Petrick HL, Dennis KMJH, Kirsh AJ, Barbeau PA, Nunes EA, Holloway GP (2020) Nitrate attenuates HFD-induced glucose intolerance in association with reduced epididymal adipose tissue inflammation and mitochondrial ROS emission. J Physiol [Epub ahead of print].|
Abstract: Evidence has accumulated to indicate that dietary nitrate alters energy expenditure and the metabolic derangements associated with a high-fat diet, however, the mechanism(s) of action remain incompletely elucidated. Therefore, we aimed to determine if dietary nitrate (4 mm sodium nitrate via drinking water) could prevent high-fat diet (HFD) mediated glucose intolerance in association with improved mitochondrial bioenergetics within both white (WAT) and brown (BAT) adipose tissue. HFD-feeding caused glucose intolerance (P < 0.05) and increased body weight. As a result of higher body weight, energy expenditure increased proportionally. HFD-fed mice displayed greater mitochondrial uncoupling and a 2-fold increase in UCP-1 content within BAT. Within epididymal adipose tissue (eWAT), HFD increased cell size (i.e. hypertrophy), mitochondrial H2O2 emission, oxidative stress, JNK phosphorylation, leucocyte infiltration, and induced insulin resistance. Remarkably, dietary nitrate consumption attenuated and/or mitigated all these responses, including rendering mitochondria more coupled within BAT, and normalizing mitochondrial H2O2 emission and insulin-mediated Akt-Thr308 phosphorylation within eWAT. Intriguingly, the positive effects of dietary nitrate appear to be independent of eWAT mitochondrial respiratory capacity and content. Altogether, these data suggest that dietary nitrate attenuates the development of HFD-induced insulin resistance in association with attenuating WAT inflammation and redox balance, independent of changes within either WAT or BAT mitochondrial respiratory capacity/content. This article is protected by copyright. All rights reserved.
Labels: MiParea: Respiration, Exercise physiology;nutrition;life style Pathology: Obesity
Organism: Mouse Tissue;cell: Fat Preparation: Permeabilized tissue Enzyme: Uncoupling protein Regulation: Uncoupler Coupling state: LEAK, OXPHOS Pathway: N, NS HRR: Oxygraph-2k, O2k-Fluorometer