Brown adipose tissue (BAT) is the primary tissue responsible for nonshivering thermogenesis in mammals. The amount of BAT and its level of activation help regulate the utilization of excessive calories for thermogenesis as opposed to storage in white adipose tissue (WAT) which would lead to weight gain. Over the past several years, BAT activity in vivo has been primarily assessed by positron emission tomography-computed tomography (PET-CT) scan using 2-[18F]-fluoro-2-deoxy-D-glucose (18F-FDG) to measure glucose utilization associated with BAT mitochondrial respiration. In this study, we demonstrate the feasibility of mapping and estimating BAT volume and metabolic function in vivo in rats at a 9.4T magnetic resonance imaging (MRI) scanner using sequences available from clinical MR scanners. Based on the morphological characteristics of BAT, we measured the volume distribution of BAT with MRI sequences that have strong fat-water contrast. We also investigated BAT volume by utilizing spin-echo MRI sequences. The in vivo MRI-estimated BAT volumes were correlated with direct measurement of BAT mass from dissected samples. Using MRI, we also were able to map hemodynamic responses to changes in BAT metabolism induced pharmacologically by β3-adrenergic receptor agonist, CL-316,243 and compare this to BAT activity in response to CL-316,243 assessed by PET 18F-FDG. In conclusion, we demonstrate the feasibility of measuring BAT volume and function in vivo using routine MRI sequences. The MRI measurement of BAT volume is consistent with quantitative measurement of the tissue ex vivo.
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http://dx.doi.org/10.1038/oby.2012.22 | DOI Listing |
Eur J Endocrinol
November 2024
Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup 2900, Denmark.
Design: The hormone secretin, best known for regulating pH in the duodenum, has anorectic properties in mice proposedly mediated via secretin-induced brown adipose tissue (BAT) activation. We investigated the effects of exogenous secretin on ad libitum food intake, BAT activity, and postprandial physiology in healthy male volunteers.
Methods: In a randomized, placebo-controlled, double-blind, crossover study, 25 healthy men underwent two 5-h i.
J Neurooncol
October 2024
IRCCS "Neuromed", via Atinense 18, 86077, Pozzilli, IS, Italy.
Eur J Haematol
October 2024
Department of Medicine, Leukemia Service, Memorial Sloan Kettering Cancer Center, New York, New York, USA.
Spleen volume reduction (SVR) is a key endpoint in inhibitors of Janus kinase (JAK) inhibitor studies. Retrospective analyses have demonstrated an association between SVR and improved overall survival (OS) among patients treated with ruxolitinib with a platelet count > 100 × 10/L. Whether this association occurs in patients with thrombocytopenia is unclear.
View Article and Find Full Text PDFBiogerontology
November 2024
Laboratory of Cardiac Structure and Function, Institute of Cardiovascular Diseases, West China Hospital, Sichuan University, Chengdu, 610041, PR China.
Neuroscientist
October 2024
Achucarro Basque Centre for Neuroscience, Leioa, Spain.
The mammalian brain comprises two structurally and functionally distinct compartments: the gray matter (GM) and the white matter (WM). In humans, the WM constitutes approximately half of the brain volume, yet it remains significantly less investigated than the GM. The major cellular elements of the WM are neuronal axons and glial cells.
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