scholarly journals Accurate quantification of brown adipose tissue mass by xenon-enhanced computed tomography

2017 ◽  
Vol 115 (1) ◽  
pp. 174-179 ◽  
Author(s):  
Rosa T. Branca ◽  
Andrew McCallister ◽  
Hong Yuan ◽  
Amir Aghajanian ◽  
James E. Faber ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Imaging Techniques ◽  
Tomographic Imaging ◽  
Obese Mouse ◽  
Vascular Perfusion ◽  
Tissue Mass ◽  
Brown Adipose ◽  
Enhanced Computed Tomography

Detection and quantification of brown adipose tissue (BAT) mass remains a major challenge, as current tomographic imaging techniques are either nonspecific or lack the necessary resolution to quantify BAT mass, especially in obese phenotypes, in which this tissue may be present but inactive. Here, we report quantification of BAT mass by xenon-enhanced computed tomography. We show that, during stimulation of BAT thermogenesis, the lipophilic gas xenon preferentially accumulates in BAT, leading to a radiodensity enhancement comparable to that seen in the lungs. This enhancement is mediated by a selective reduction in BAT vascular resistance, which greatly increases vascular perfusion of BAT. This enhancement enables precise identification and quantification of BAT mass not only in lean, but also in obese, mouse phenotypes, in which this tissue is invisible to conventional tomographic imaging techniques. The method is developed and validated in rodents and then applied in macaques to assess its feasibility in larger species.

scholarly journals Reduced Expression of Urokinase Plasminogen Activator in Brown Adipose Tissue of Obese Mouse Models

2021 ◽  
Vol 22 (7) ◽  
pp. 3407
Author(s):  
Chung-Ze Wu ◽  
Li-Chien Chang ◽  
Chao-Wen Cheng ◽  
Te-Chao Fang ◽  
Yuh-Feng Lin ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Glomerular Filtration Rate ◽  
Brown Adipose Tissue ◽  
Glomerular Filtration ◽  
Plasminogen Activator ◽  
Mouse Models ◽  
Filtration Rate ◽  
Obese Mouse ◽  
Adipose Tissues ◽  
Brown Adipose

In recent decades, the obesity epidemic has resulted in morbidity and mortality rates increasing globally. In this study, using obese mouse models, we investigated the relationship among urokinase plasminogen activator (uPA), metabolic disorders, glomerular filtration rate, and adipose tissues. Two groups, each comprised of C57BL/6J and BALB/c male mice, were fed a chow diet (CD) and a high fat diet (HFD), respectively. Within the two HFD groups, half of each group were euthanized at 8 weeks (W8) or 16 weeks (W16). Blood, urine and adipose tissues were collected and harvested for evaluation of the effects of obesity. In both mouse models, triglyceride with insulin resistance and body weight increased with duration when fed a HFD in comparison to those in the groups on a CD. In both C57BL/6J and BALB/c HFD mice, levels of serum uPA initially increased significantly in the W8 group, and then the increment decreased in the W16 group. The glomerular filtration rate declined in both HFD groups. The expression of uPA significantly decreased in brown adipose tissue (BAT), but not in white adipose tissue, when compared with that in the CD group. The results suggest a decline in the expression of uPA in BAT in obese m models as the serum uPA increases. There is possibly an association with BAT fibrosis and dysfunction, which may need further study.

Effects of fasting and food restriction on brown adipose tissue composition in normal and dystrophic hamsters

1986 ◽  
Vol 64 (7) ◽  
pp. 970-975 ◽  
Author(s):  
M. Desautels ◽  
R. A. Dulos ◽  
H. M. Yuen
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Food Deprivation ◽  
Food Restriction ◽  
Tissue Mass ◽  
Tissue Protein ◽  
Guanosine Diphosphate ◽  
Isolated Mitochondria ◽  
Daily Food ◽  
Brown Adipose

Fasting for 36–48 h or food restriction (30% reduction of daily food intake for 6 weeks) caused brown adipose tissue (BAT) atrophy in hamsters. Fasting-induced atrophy was characterized by reductions in tissue mass, DNA, protein, and thermogenin. By contrast, food restriction had no effect on tissue cellularity (DNA) but markedly reduced the tissue protein and thermogenin contents. The concentration of thermogenin in isolated mitochondria was unchanged by fasting or food restriction. Dystrophic hamsters had a reduced BAT mass when compared with weight-matched control hamsters. This resulted from a reduction in tissue cellularity since BAT DNA, protein and thermogenin contents were all reduced. The extent of binding of [3H]guanosine diphosphate to isolated mitochondria and their content of thermogenin were similar in normal and dystrophic hamsters. In response to cold exposure, as in normal hamsters, BAT of dystrophic hamsters grew and the tissue thermogenin increased, but the mitochondrial concentration of thermogenin did not change. In response to fasting, in contrast with normal hamsters, there was no significant reduction in BAT DNA in dystrophic animals and the loss of tissue protein was reduced. However, the relative changes in BAT composition during chronic food restriction were similar in normal and dystrophic animals. Thus, reduction in hamster BAT thermogenic capacity during food deprivation may occur by loss of cells and (or) reduction in the tissue protein and thermogenin contents. The extent of protein and (or) DNA loss may be dependent upon the original tissue mass and the severity of food deprivation.

Caloric Restriction Paradoxically Increases Adiposity in Mice With Genetically Reduced Insulin

Endocrinology ◽  
2016 ◽  
Vol 157 (7) ◽  
pp. 2724-2734 ◽  
Author(s):  
Derek A. Dionne ◽  
Søs Skovsø ◽  
Nicole M. Templeman ◽  
Susanne M. Clee ◽  
James D. Johnson
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Caloric Restriction ◽  
Gene Dosage ◽  
Tissue Growth ◽  
Tissue Mass ◽  
Brown Adipose ◽  
Paradoxical Effects ◽  
Plasma Insulin Levels ◽  
Ad Libitum

Antiadiposity effects of caloric restriction (CR) are associated with reduced insulin/IGF-1 signaling, but it is unclear whether the effects of CR would be additive to genetically reducing circulating insulin. To address this question, we examined female Ins1+/−:Ins2−/− mice and Ins1+/+:Ins2−/− littermate controls on either an ad libitum or 60% CR diet. Although Igf1 levels declined as expected, CR was unable to reduce plasma insulin levels in either genotype below their ad libitum-fed littermate controls. In fact, 53-week-old Ins1+/−:Ins2−/− mice exhibited a paradoxical increase in circulating insulin in the CR group compared with the ad libitum-fed Ins1+/−:Ins2−/− mice. Regardless of insulin gene dosage, CR mice had lower fasting glucose and improved glucose tolerance. Although body mass and lean mass predictably fell after CR initiation, we observed a significant and unexpected increase in fat mass in the CR Ins1+/−:Ins2−/− mice. Specifically, inguinal fat was significantly increased by CR at 66 weeks and 106 weeks. By 106 weeks, brown adipose tissue mass was also significantly increased by CR in both Ins1+/−:Ins2−/− and Ins1+/+:Ins2−/− mice. Interestingly, we observed a clear whitening of brown adipose tissue in the CR groups. Mice in the CR group had altered daily energy expenditure and respiratory exchange ratio circadian rhythms in both genotypes. Multiplexed analysis of circulating hormones revealed that CR was associated with increased fasting and fed levels of the obesogenic hormone, glucose-dependent insulinotropic polypeptide. Collectively these data demonstrate CR has paradoxical effects on adipose tissue growth in the context of genetically reduced insulin.

Fibroblast Growth Factor-9 Regulates Adaptive Brown Adipose Tissue Mass Expansion

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 277-OR ◽  
Author(s):  
FARNAZ SHAMSI ◽  
TIAN LIAN HUANG ◽  
YU-HUA TSENG
Keyword(s):  
Adipose Tissue ◽  
Growth Factor ◽  
Brown Adipose Tissue ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth ◽  
Tissue Mass ◽  
Brown Adipose ◽  
Adipose Tissue Mass ◽  
Mass Expansion

scholarly journals Metabolic Alterations in Patients with Pheochromocytoma

2018 ◽  
Vol 127 (02/03) ◽  
pp. 129-136 ◽  
Author(s):  
Zoran Erlic ◽  
Felix Beuschlein
Keyword(s):  
Experimental Data ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Imaging Techniques ◽  
Clinical Manifestations ◽  
Case Series ◽  
Metabolic Rates ◽  
Metabolic Alterations ◽  
Clinical Observations ◽  
Brown Adipose

AbstractMetabolic alterations in patients with hormonally active pheochromocytoma/paraganglioma (PPGL) have been described early on in the literature. The initial findings were related to disturbed glucose homeostasis and lipolysis activation, as well as elevated metabolic rates in affected patients. Similarly, from early autopsy reports, the presence of brown adipose tissue had been noted in PPGL patients. In more recent years, changes in body weight, fat mass and distribution have been analyzed in more detail in addition to activity of brown adipose tissue based on functional imaging techniques. Over the last decades, several larger case series and cohort studies have contributed towards the elucidation of possible mechanism contributing to these clinical observations. Herein, we summarize the clinical and experimental data regarding metabolic alterations and related clinical manifestations in PPGL patients.

Control mechanisms in brown adipose tissue plasma membrane

1984 ◽  
Vol 62 (7) ◽  
pp. 631-636 ◽  
Author(s):  
N. Bégin-Heick ◽  
H. M. C. Heick
Keyword(s):  
Adipose Tissue ◽  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Brown Adipose Tissue ◽  
Heat Production ◽  
Metabolic Effects ◽  
Maximal Response ◽  
Obese Mouse ◽  
Control Mechanisms ◽  
Brown Adipose

It is generally agreed that the site of heat production during nonshivering thermogenesis is the brown adipose tissue (BAT) and that the triggering event for heat production is the interaction of noradrenaline (NA) with its receptor on the plasma membrane. Following this initial event, several changes occur which result in increased rates of cAMP synthesis, redistribution of ions across the membrane, enhanced rates of lipolysis, and increased mitochondrial oxidation of substrates. BAT is also a target for the anabolic effect of insulin. Available evidence shows that insulin receptors are present on the BAT plasma membrane and that insulin can oppose the metabolic effects of catecholamine on BAT. We have studied more particularly the response of BAT adenylate cyclase to catecholamines in an animal model (the ob/ob mouse) which has a defective thermogenic response. The capacity of adenylate cyclase to be stimulated by catecholamines was significantly less in the tissue of obese mice than in lean controls. To produce a response equal to the half-maximal response in the lean mouse, a 10-fold increase in the NA concentration was required in the BAT of the obese mouse. These results are in harmony with those of others showing that the lipolytic response to catecholamines is abnormal in the BAT of the obese mouse. The adenylate cyclase activity can be altered by changes in the lipid composition of the diet and by manipulation of hormone levels. It is likely that the alteration in adenylate cyclase responsiveness is one of the contributing factors in the impaired thermogenesis and obesity in this animal.

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