Brown adipose tissue dynamics in wild-type and UCP1-knockout mice: in vivo insights with magnetic resonance

Autor: Steve Braun, Kirsten Grimpo, Gerhard Heldmaier, Eva N. Heppe, Johannes T. Heverhagen, Maximilian N. Völker
Rok vydání: 2014
Předmět:
medicine.medical_specialty
Magnetic Resonance Spectroscopy
Phosphocreatine
Acclimatization
uncoupling protein 1
Adipose tissue
QD415-436
Oxidative phosphorylation
Fatty Acids
Nonesterified
Biology
Biochemistry
Ion Channels
Oxidative Phosphorylation
Mitochondrial Proteins
Mice
Norepinephrine
chemistry.chemical_compound
Adenosine Triphosphate
Oxygen Consumption
Endocrinology
Adipose Tissue
Brown
Internal medicine
lipid metabolism
Brown adipose tissue
medicine
Animals
ultra-high field
Research Articles
Mice
Knockout
nonshivering thermogenesis
Thermogenesis
Lipid metabolism
Cell Biology
Magnetic Resonance Imaging
Thermogenin
Adenosine Diphosphate
Cold Temperature
Adenosine diphosphate
medicine.anatomical_structure
chemistry
lipids (amino acids
peptides
and proteins)
phosphorus spectroscopy
proton spectroscopy
Zdroj: Journal of Lipid Research, Vol 55, Iss 3, Pp 398-409 (2014)
ISSN: 0022-2275
DOI: 10.1194/jlr.m042895
Popis: We used noninvasive magnetic resonance imaging (MRI) and magnetic resonance spectroscopy to compare interscapular brown adipose tissue (iBAT) of wild-type (WT) and uncoupling protein 1 (UCP1)-knockout mice lacking UCP1-mediated nonshivering thermogenesis (NST). Mice were sequentially acclimated to an ambient temperature of 30°C, 18°C, and 5°C. We detected a remodeling of iBAT and a decrease in its lipid content in all mice during cold exposure. Ratios of energy-rich phosphates (ATP/ADP, phosphocreatine/ATP) in iBAT were maintained stable during noradrenergic stimulation of thermogenesis in cold- and warm-adapted mice and no difference between the genotypes was observed. As free fatty acids (FFAs) serve as fuel for thermogenesis and activate UCP1 for uncoupling of oxidative phosphorylation, brown adipose tissue is considered to be a main acceptor and consumer of FFAs. We measured a major loss of FFAs from iBAT during noradrenergic stimulation of thermogenesis. This mobilization of FFAs was observed in iBAT of WT mice as well as in mice lacking UCP1. The high turnover and the release of FFAs from iBAT suggests an enhancement of lipid metabolism, which in itself contributes to the sympathetically activated NST and which is independent from uncoupled respiration mediated by UCP1. Our study demonstrates that MRI, besides its potential for visualizing and quantification of fat tissue, is a valuable tool for monitoring functional in vivo processes like lipid and phosphate metabolism during NST.
Databáze: OpenAIRE
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