scholarly journals Diurnal variations of brown fat thermogenesis and fat oxidation in humans

2021 ◽  
Author(s):  
Mami Matsushita ◽  
Shinsuke Nirengi ◽  
Masanobu Hibi ◽  
Hitoshi Wakabayashi ◽  
Sang-il Lee ◽  
...  
Keyword(s):  
Metabolic Disorders ◽  
Fat Oxidation ◽  
Diurnal Variations ◽  
Whole Body ◽  
Breakfast Skipping ◽  
Healthy Humans ◽  
Positron Emission ◽  
Brown Adipose ◽  
Increased Risk ◽  
Diet Induced Thermogenesis

Abstract Background/objectives Disturbed circadian rhythm is associated with an increased risk of obesity and metabolic disorders. Brown adipose tissue (BAT) is a site of nonshivering thermogenesis (NST) and plays a role in regulating whole-body energy expenditure (EE), substrate metabolism, and body fatness. In this study, we examined diurnal variations of NST in healthy humans by focusing on their relation to BAT activity. Methods Forty-four healthy men underwent 18F-fluoro-2-deoxy-D-glucose positron emission tomography and were divided into Low-BAT and High-BAT groups. In STUDY 1, EE, diet-induced thermogenesis (DIT), and fat oxidation (FO) were measured using a whole-room indirect calorimeter at 27 °C. In STUDY 2, EE, FO, and skin temperature in the region close to BAT depots (Tscv) and in the control region (Tc) were measured at 27 °C and after 90 min cold exposure at 19 °C in the morning and in the evening. Results In STUDY 1, DIT and FO after breakfast was higher in the High-BAT group than in the Low-BAT group (P < 0.05), whereas those after dinner were comparable in the two groups. FO in the High-BAT group was higher after breakfast than after dinner (P < 0.01). In STUDY 2, cold-induced increases in EE (CIT), FO, and Tscv relative to Tc in the morning were higher in the High-BAT group than in the Low-BAT group (P < 0.05), whereas those after dinner were comparable in the two groups. CIT in the High-BAT group tended to be higher in the morning than in the evening (P = 0.056). Conclusion BAT-associated NST and FO were evident in the morning, but not in the evening, suggesting that the activity of human BAT is higher in the morning than in the evening, and thus may be involved in the association of an eating habit of breakfast skipping with obesity and related metabolic disorders.

scholarly journals Brown adipose tissue is involved in diet-induced thermogenesis and whole-body fat utilization in healthy humans

2016 ◽  
Vol 40 (11) ◽  
pp. 1655-1661 ◽  
Author(s):  
M Hibi ◽  
S Oishi ◽  
M Matsushita ◽  
T Yoneshiro ◽  
T Yamaguchi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Body Fat ◽  
Whole Body ◽  
Fat Utilization ◽  
Healthy Humans ◽  
Brown Adipose ◽  
Diet Induced Thermogenesis

scholarly journals DsbA-L deficiency in T cells promotes diet-induced thermogenesis through suppressing IFN-γ production

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haiyan Zhou ◽  
Xinyi Peng ◽  
Jie Hu ◽  
Liwen Wang ◽  
Hairong Luo ◽  
...  
Keyword(s):  
T Cells ◽  
Adipose Tissue ◽  
T Cell ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Therapeutic Potential ◽  
Whole Body ◽  
Brown Adipose ◽  
Ifn Γ ◽  
Diet Induced Thermogenesis

AbstractAdipose tissue-resident T cells have been recognized as a critical regulator of thermogenesis and energy expenditure, yet the underlying mechanisms remain unclear. Here, we show that high-fat diet (HFD) feeding greatly suppresses the expression of disulfide-bond A oxidoreductase-like protein (DsbA-L), a mitochondria-localized chaperone protein, in adipose-resident T cells, which correlates with reduced T cell mitochondrial function. T cell-specific knockout of DsbA-L enhances diet-induced thermogenesis in brown adipose tissue (BAT) and protects mice from HFD-induced obesity, hepatosteatosis, and insulin resistance. Mechanistically, DsbA-L deficiency in T cells reduces IFN-γ production and activates protein kinase A by reducing phosphodiesterase-4D expression, leading to increased BAT thermogenesis. Taken together, our study uncovers a mechanism by which T cells communicate with brown adipocytes to regulate BAT thermogenesis and whole-body energy homeostasis. Our findings highlight a therapeutic potential of targeting T cells for the treatment of over nutrition-induced obesity and its associated metabolic diseases.

scholarly journals 1293 Hibernoma: Rare Case of An Intense 18F-FDG Uptake Mediastinal Lesion Mimicking Thymic Carcinoma

2021 ◽  
Vol 108 (Supplement_6) ◽  
Author(s):  
C Ndukauba ◽  
J Coelho-Lima ◽  
K Pai ◽  
D Gey Van Pittius ◽  
C Satur
Keyword(s):  
Unusual Case ◽  
Thymic Carcinoma ◽  
Whole Body ◽  
Histopathological Analysis ◽  
Cardiac Pathology ◽  
Local Structures ◽  
Positron Emission ◽  
Brown Adipose ◽  
Vacuolated Cells ◽  
Very High

Abstract Hibernoma is a rare benign neoplasia derived from remnants of brown adipose tissue. Here, we describe an unusual case of mediastinal hibernoma which radiologically mimicked a thymic malignancy. The patients had presented with chest pain, associated with palpitations and dizziness suggestive of cardiac pathology. Investigation of coronary anatomy by CT scan, incompletely revealed the presence of the lesion situated in the region of the thymus gland, 48 mm x 94 mm. The mass was smooth walled with evidence of invasion of local structures. Whole-body positron-emission tomography (PET) demonstrated the mass had a very high uptake, SUV 55.2. The mass was excised by total thymectomy through a sternotomy. Histopathological analysis revealed it to be fibro-fatty in nature. Light microscopy demonstrated the presence of large multi-vacuolated cells, with appearances typical of brown fat, a hibernoma. This is one of only 7 reported cases. Its findings highlight the importance of careful interpretation of PET studies in hibernoma cases. We propose hibernoma should be included as a differential diagnosis of growing mediastinal masses.

scholarly journals Brown Adipose Tissue - role in metabolic disorders

2019 ◽  
Vol 13 (1) ◽  
pp. 002
Author(s):  
Tahniyah Haq ◽  
Frank Joseph Ong ◽  
Sarah Kanji
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Metabolic Diseases ◽  
Uncoupling Protein ◽  
Whole Body ◽  
Positron Emission ◽  
Brown Adipose ◽  
Magnetic Resonance Imaging Mri ◽  
Fdg Pet Ct ◽  
Body Energy

Brown adipose tissue, a thermogenic organ, previously thought to be present in only small mammals and children has recently been identified in adult humans. Located primarily in the supraclavicular and cervical area, it produces heat by uncoupling oxidative phosphorylation due to the unique presence of uncoupling protein 1 by a process called nonshivering thermogenesis. BAT activity depends on many factors including age, sex, adiposity and outdoor temperature. Positron-emission tomography using 18F-fluorodeoxyglucose and computed tomography (18F-FDG PET–CT), magnetic resonance imaging (MRI) and thermal imaging (IRT) are among several methods used to detect BAT in humans. The importance of BAT is due to its role in whole body energy expenditure and fuel metabolism. Thus it is postulated that it may be useful in the treatment of metabolic diseases. However, there are still many unanswered questions to the clinical usefulness of this novel tissue. IMC J Med Sci 2019; 13(1): 002

scholarly journals Leucine Potentiates Glucose-mediated 18F-FDG Uptake in Brown Adipose Tissue via β-Adrenergic Activation

Biomedicines ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 159
Author(s):  
Brenda Huska ◽  
Sarah Niccoli ◽  
Christopher P. Phenix ◽  
Simon J. Lees
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Whole Body ◽  
Fdg Uptake ◽  
Standardized Uptake Values ◽  
Positron Emission ◽  
Brown Adipose ◽  
18F Fdg ◽  
Adrenergic Activation

Significant depots of brown adipose tissue (BAT) have been identified in many adult humans through positron emission tomography (PET), with the amount of BAT being inversely correlated with obesity. As dietary activation of BAT has implications for whole body glucose metabolism, leucine was used in the present study to determine its ability to promote BAT activation resulting in increased glucose uptake. In order to assess this, 2-deoxy-2-(fluorine-18)fluoro-d-glucose (18F-FDG) uptake was measured in C57BL/6 mice using microPET after treatment with leucine, glucose, or both in interscapular BAT (IBAT). Pretreatment with propranolol (PRP) was used to determine the role of β-adrenergic activation in glucose and leucine-mediated 18F-FDG uptake. Analysis of maximum standardized uptake values (SUVMAX) determined that glucose administration increased 18F-FDG uptake in IBAT by 25.3%. While leucine did not promote 18F-FDG uptake alone, it did potentiate glucose-mediated 18F-FDG uptake, increasing 18F-FDG uptake in IBAT by 22.5%, compared to glucose alone. Pretreatment with PRP prevented the increase in IBAT 18F-FDG uptake following the combination of glucose and leucine administration. These data suggest that leucine is effective in promoting BAT 18F-FDG uptake through β-adrenergic activation in combination with glucose.

Reduced lipogenesis in cafeteria-fed rats exhibiting diet-induced thermogenesis

1983 ◽  
Vol 3 (3) ◽  
pp. 217-224 ◽  
Author(s):  
Nancy J. Rothwell ◽  
Michael J. Stock ◽  
Paul Trayhurn
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Whole Body ◽  
Stock Diet ◽  
Inhibitory Effects ◽  
Brown Adipose ◽  
Diet Induced Thermogenesis

Fatty-acid synthesis has been measured in vivo with 3H2O in cafeteria-fed rats exhibiting diet-induced thermogenesis. Synthesis was decreased in brown adipose tissue, the liver, white adipose tissue, and the carcass of the cafeteria-fed animals compared to rats fed the normal stock diet. Whole-body synthesis was also decreased in the cafeteria-fed group. Diet-induced thermogenesis, in contrast to cold-induced non-shivering thermogenesis does not lead to increased fatty-acid synthesis and this is presumably due to the inhibitory effects on lipogenesis of the high dietary fat intake characteristic of cafeteria diets. The results also indicate that the energy cost of body fat deposition in cafeteria-fed rats is lower than in animals fed a low-fat/high-carbohydrate stock diet.

scholarly journals Brown adipose tissue: what have we learned since its recent identification in human adults

2014 ◽  
Vol 58 (9) ◽  
pp. 889-899 ◽  
Author(s):  
Bruno Halpern ◽  
Marcio Correa Mancini ◽  
Alfredo Halpern
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Mitochondrial Uncoupling ◽  
Positron Emission ◽  
Brown Adipose ◽  
Adult Humans ◽  
Human Adults ◽  
Real Importance ◽  
Diet Induced Thermogenesis ◽  
Fluorodeoxyglucose Pet

Brown adipose tissue, an essential organ for thermoregulation in small and hibernating mammals due to its mitochondrial uncoupling capacity, was until recently considered to be present in humans only in newborns. The identification of brown adipose tissue in adult humans since the development and use of positron emission tomography marked with 18-fluorodeoxyglucose (PET-FDG) has raised a series of doubts and questions about its real importance in our metabolism. In this review, we will discuss what we have learnt since its identification in humans as well as both new and old concepts, some of which have been marginalized for decades, such as diet-induced thermogenesis. Arq Bras Endocrinol Metab. 2014;58(9):889-99

Brown adipose tissue, liver, and diet-induced thermogenesis in cafeteria diet-fed rats

1989 ◽  
Vol 67 (4) ◽  
pp. 376-381 ◽  
Author(s):  
Stephanie W. Y. Ma ◽  
David O. Foster
Keyword(s):  
Blood Flow ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Direct Determination ◽  
Metabolizable Energy ◽  
Whole Body ◽  
Tissue Blood Flow ◽  
Direct Measurements ◽  
Brown Adipose ◽  
Diet Induced Thermogenesis

Diet-induced thermogenesis (DIT) in young rats overeating a "cafeteria" (CAF) diet of palatable human foods is characterized by a chronic, propranolol-inhibitable elevation in resting metabolic rate [Formula: see text] and is associated with various changes in brown adipose tissue (BAT) that have been taken as evidence for BAT as the effector of DIT. But direct evidence for participation of BAT in DIT has been lacking. By employing a nonocclusive cannula to sample the venous effluent of interscapular BAT (IBAT) for analysis of its O2 content and measuring tissue blood flow with microspheres, we accomplished direct determination (Fick principle) of the O2 consumption of BAT in conscious CAF rats. In comparison with normophagic controls fed chow, the CAF rats exhibited a 43% increase in metabolizable energy intake, reduced food efficiency, a 22% elevation in resting [Formula: see text] at 28 °C (thermoneutrality) or 24 °C (housing temperature), and characteristic changes in the properties of their BAT (e.g., increased mass, protein content and mitochondrial GDP binding). They also exhibited the greater metabolic response to exogenous noradrenaline characteristic of CAF rats and the near elimination by propranolol of their elevation in [Formula: see text]. By the criterion of their elevated [Formula: see text], the CAF rats were exhibiting DIT at the time of the measurements of BAT blood flow and blood O2 levels. However, BAT O2 consumption was found to be no greater in the CAF rats than in the controls at either 28 or 24 °C. At 28 °C it accounted for less than 1% of whole body [Formula: see text]; at 24 °C it increased to about 10% of overall [Formula: see text] in both diet groups. Direct measurements of BAT O2 consumption during expression of the thermic response to a tube-fed meal were also made in conscious CAF and control rats. Both diet groups exhibited an approximately 15% increase in whole body [Formula: see text] at 90–120 min after the meal. The contribution by BAT to this increase was only 2–3% and did not differ significantly between groups. Thus, the results of these direct measurements of BAT O2 consumption in vivo do not support the theory that DIT in CAF rats is mainly due to increased BAT thermogenesis occurring either chronically or during assimilation of a meal. In further studies of the effector(s) of DIT in CAF rats, partial hepatectomy (two-thirds of the liver removed) was found to acutely reduce the resting [Formula: see text] of CAF rats by 1.85 mL/min, 2.3 times as much as in chow-fed controls. From this difference in response, it was estimated that in the CAF rats liver O2 consumption before hepatectomy exceeded that of the controls by about 1.5 mL/min, an amount that would be sufficient to fully account for the elevation in resting [Formula: see text] of the former. A major role for the liver in the DIT of CAF rats is thus suggested.Key words: cafeteria feeding, diet-induced thermogenesis, thermic effect of food, brown fat, liver.

scholarly journals Intravenous and oral copper kinetics, biodistribution and dosimetry in healthy humans studied by [64Cu]copper PET/CT

2020 ◽  
Author(s):  
Kristoffer Kjærgaard ◽  
Thomas Damgaard Sandahl ◽  
Kim Frisch ◽  
Karina Højrup ◽  
Susanne Keiding ◽  
...  
Keyword(s):  
Oral Administration ◽  
Effective Dose ◽  
Intravenous Administration ◽  
Radiation Dosimetry ◽  
The Body ◽  
Whole Body ◽  
Healthy Humans ◽  
Positron Emission ◽  
Pet Ct ◽  
Intravenous And Oral Administration

Abstract Purpose: Copper is essential for enzymatic processes throughout the body. [64Cu]copper (64Cu) positron emission tomography (PET) has been investigated as a diagnostic tool for certain malignancies, but has not yet been used to study copper homeostasis in humans. In this study, we determined the hepatic removal kinetics, biodistribution and radiation dosimetry of 64Cu in healthy humans by both intravenous and oral administration. Methods: Six healthy participants underwent PET/CT studies with intravenous or oral administration of 64Cu. A 90 min dynamic PET/CT scan of the liver was followed by three whole-body PET/CT scans at 1.5, 6, and 20 h after tracer administration. PET data were used for estimation of hepatic kinetics, biodistribution, effective doses, and absorbed doses for critical organs. Results: After intravenous administration, 64Cu uptake was highest in the liver, intestinal walls and pancreas; the gender-averaged effective dose was 62 ± 5 μSv/MBq (mean ± SD). After oral administration, 64Cu was almost exclusively taken up by the liver while leaving a significant amount of radiotracer in the gastrointestinal lumen, resulting in an effective dose of 113 ± 1 μSv/MBq. Excretion of 64Cu in urine and faeces after intravenous administration was negligible. Hepatic removal kinetics showed that the clearance of 64Cu from blood was 0.10 ± 0.02 mL blood/min/mL liver tissue, and the rate constant for excretion into bile or blood was 0.003 ± 0.002 min-1. Conclusion: 64Cu biodistribution and radiation dosimetry are influenced by the manner of tracer administration with high uptake by the liver, intestinal walls, and pancreas after intravenous administration, and after oral administration, 64Cu is rapidly absorbed from the gastrointestinal tract and deposited primarily in the liver. Administration of 50 MBq 64Cu yielded images of high quality for both administration forms with radiation doses approximately 3.1 and 5.7 mSv, respectively, allowing for sequential studies in humans.Trial Registration Number: EudraCT no. 2016-001975-59. Registration date: 19/09/2016.

Unexpected evidence for active brown adipose tissue in adult humans

2007 ◽  
Vol 293 (2) ◽  
pp. E444-E452 ◽  
Author(s):  
Jan Nedergaard ◽  
Tore Bengtsson ◽  
Barbara Cannon
Keyword(s):  
Human Physiology ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Tracer Uptake ◽  
Interscapular Brown Adipose Tissue ◽  
Positron Emission ◽  
Brown Adipose ◽  
Adult Humans ◽  
Brown Adipose Tissue Activity ◽  
Diet Induced Thermogenesis

The contention that brown adipose tissue is absent in adult man has meant that processes attributed to active brown adipose tissue in experimental animals (mainly rodents), i.e., classical nonshivering thermogenesis, adaptive adrenergic thermogenesis, diet-induced thermogenesis, and antiobesity, should be either absent or attributed to alternative (unknown) mechanisms in man. However, serendipidously, as a consequence of the use of fluorodeoxyglucose positron emission tomography (FDG PET) to trace tumor metastasis, observations that may change that notion have recently been made. These tomography scans have visualized symmetrical areas of increased tracer uptake in the upper parts of the human body; these areas of uptake correspond to brown adipose tissue. We examine here the published observations from a viewpoint of human physiology. The human depots are somewhat differently located from those in rodents, the main depots being found in the supraclavicular and the neck regions with some additional paravertebral, mediastinal, para-aortic, and suprarenal localizations (but no interscapular). Brown adipose tissue activity in man is acutely cold induced and is stimulated via the sympathetic nervous system. The prevalence of active brown adipose tissue in normal adult man can be only indirectly estimated, but it would seem that the prevalence of active brown adipose tissue in the population may be at least in the range of some tens of percent. We conclude that a substantial fraction of adult humans possess active brown adipose tissue that thus has the potential to be of metabolic significance for normal human physiology as well as to become pharmaceutically activated in efforts to combat obesity.

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