Bone marrow fat has brown adipose tissue characteristics, which are attenuated with aging and diabetes

This chapter considers the more obscure non-white types of adipose tissue present in the human body. The first and better-known type discussed is brown fat, which contributes to the regulation of body temperature as it burns (excess) calories to generate heat. The second section explores the biology of bone marrow fat, whose enigmatic behaviour in the context of starvation and obesity does little to help define its role. After considering the relationship between bone marrow adipose tissue, bone strength, and overall metabolic health, this chapter concludes by briefly reviewing other, lesser-known types of (white) fat (e.g., epicardial fat) and their potential contribution to human biology.

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Active Cushing syndrome patients have increased ectopic fat deposition and bone marrow fat content compared to cured patients and healthy subjects: a pilot 1H-MRS study

Acta Endocrinologica ◽

10.1530/eje-18-0318 ◽

2018 ◽

Vol 179 (5) ◽

pp. 307-317 ◽

Cited By ~ 10

Author(s):

F Maurice ◽

A Dutour ◽

C Vincentelli ◽

I Abdesselam ◽

M Bernard ◽

...

Keyword(s):

Bone Marrow ◽

Adipose Tissue ◽

Cushing Syndrome ◽

Cross Sectional Study ◽

Mineral Density ◽

Marrow Fat ◽

1H Mrs ◽

Cross Sectional ◽

Bone Marrow Fat ◽

Main Regulator

Objective Glucocorticoid excess is one of the most important causes of bone disorders. Bone marrow fat (BMF) has been identified as a new mediator of bone metabolism. Cushing syndrome (CS) is a main regulator of adipose tissue distribution but its impact on BMF is unknown. The objective of the study was to evaluate the effect of chronic hypercortisolism on BMF. Design This was a cross-sectional study. Seventeen active and 17 cured ACTH-dependent CS patients along with 17 controls (matched with the active group for age and sex) were included. Methods The BMF content of the femoral neck and L3 vertebrae were measured by 1H-MRS on a 3-Tesla wide-bore magnet. Bone mineral density (BMD) was evaluated in patients using dual-energy X-ray absorptiometry. Results Active CS patients had higher BMF content both in the femur (82.5 ± 2.6%) and vertebrae (70.1 ± 5.1%) compared to the controls (70.8 ± 3.6%, P = 0.013 and 49.0 ± 3.7% P = 0.005, respectively). In cured CS patients (average remission time of 43 months), BMF content was not different from controls at both sites (72.3 ± 2.9% (femur) and 46.7% ± 5.3% (L3)). BMF content was positively correlated with age, fasting plasma glucose, HbA1c, triglycerides and visceral adipose tissue in the whole cohort and negatively correlated with BMD values in the CS patients. Conclusions Accumulation of BMF is induced by hypercortisolism. In remission patients, BMF reached values of controls. Further studies are needed to determine whether this increase in marrow adiposity in CS is associated with bone loss.

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The influence of adipose tissue and bone marrow fat on bone mineral density in short bowel syndrome

Endocrine Abstracts ◽

10.1530/endoabs.56.gp56 ◽

2018 ◽

Author(s):

Luciana Parreiras-e-Silva ◽

Araujo Iana de ◽

Carlos Salmon ◽

Julio Marchini ◽

Vivian Suen ◽

...

Keyword(s):

Bone Mineral Density ◽

Bone Marrow ◽

Adipose Tissue ◽

Short Bowel Syndrome ◽

Bone Mineral ◽

Mineral Density ◽

Marrow Fat ◽

Short Bowel ◽

Bone Marrow Fat

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Seasonal Changes in Endocannabinoid Concentrations between Active and Hibernating Marmots (Marmota flaviventris)

Journal of Biological Rhythms ◽

10.1177/0748730418777660 ◽

2018 ◽

Vol 33 (4) ◽

pp. 388-401 ◽

Cited By ~ 6

Author(s):

Emily A. Mulawa ◽

Jay S. Kirkwood ◽

Lisa M. Wolfe ◽

Samantha J. Wojda ◽

Jessica E. Prenni ◽

...

Keyword(s):

Bone Marrow ◽

Adipose Tissue ◽

Energy Metabolism ◽

Brown Adipose Tissue ◽

Cortical Bone ◽

White Adipose Tissue ◽

Endocannabinoid System ◽

Negative Consequences ◽

Marmota Flaviventris ◽

Brown Adipose

Hibernation is a naturally occurring model for studying diseases such as obesity and osteoporosis. Hibernators, marmots (Marmota flaviventris) among them, are able to nearly double their body mass by increasing fat stores prior to hibernation without the negative consequences of obesity. They are also physically inactive for extended periods of time without experiencing negative effects on the skeleton. The endocannabinoid system is involved in modulating neural signaling, circannual rhythms, behavior, appetite, thermogenesis, and bone and energy metabolism. These systems are also altered to maintain homeostasis during hibernation. This study aims to better understand the involvement of the endocannabinoid system in the regulation of physiological processes during hibernation by quantifying the seasonal variation of endocannabinoids and endocannabinoid-like ligands in both active and hibernating marmots. We hypothesized that there would be significant changes in endocannabinoid concentrations at the tissue level in marmots between active and hibernating states. Concentrations were measured in brain, serum, brown adipose tissue, white adipose tissue, bone marrow, cortical bone, and trabecular bone using microflow chromatography coupled with tandem quadrupole mass spectrometry. Significant changes were found, such as a 30-fold decrease in 2-arachidonoyl glycerol (2-AG) in cortical bone during hibernation. Many endocannabinoid and endocannabinoid-like ligands decreased in brown adipose tissue, white adipose tissue, and cortical bone, while several ligands increased in bone marrow. This result supports our hypothesis and suggests the possibility of a peripherally controlled shift in energy metabolism, reduction in bone metabolism, and suppression of the immune system during hibernation.

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Morphological and functional characteristics of cryopreserved multipotent mesenchymal stromal cells from bone marrow, adipose tissue and tendons

Cell and Organ Transplantology ◽

10.22494/cot.v4i2.64 ◽

2016 ◽

Vol 4 (2) ◽

pp. 200-205 ◽

Cited By ~ 2

Author(s):

N. Volkovа ◽

M. Yukhta ◽

A. Goltsev

Keyword(s):

Bone Marrow ◽

Adipose Tissue ◽

Stromal Cells ◽

Colony Formation ◽

Type I Collagen ◽

Membrane Integrity ◽

Multipotent Mesenchymal Stromal Cells ◽

Type I ◽

Marrow Fat ◽

Bone Marrow Fat

The aim of study was to comparatively evaluate the morphological and functional properties of cryopreserved multipotent mesenchymal stromal cells (MMSCs) from bone marrow, fat and tendon.Materials and methods. MMSC cultures obtained from rat bone marrow, fat and tendon. The cells was cryopreserved under protection of 10 % DMSO and 20% FBS with cooling rate of 1 deg/min down to -80°C followed by plunging into liquid nitrogen. In the studied cultures the membrane integrity, immunophenotype, ability to colony formation, proliferative characteristics (MTT-test), directed differentiation and type I collagen synthesis were evaluated.Results. Investigated cryopreserved cell culture derived from bone marrow, tendon and adipose tissue had high membrane integrity indicators, colony formation and proliferation as well as the ability to directional adipogenic and chondrogenic differentiation. The analysis of immunophenotype showed that the tested cryopreserved MMSCs culture characterized by high levels of expression (≥90 %) of CD44, CD90, CD105, CD73 and low expression (≤1 %) of hematopoietic marker CD45. Cryopreserved bone marrow MMSCs were characterized by a high content of cells that synthesized type I collagen as compared to cultures which were derived from fat and tendon.Conclusions. Cell cultures derived from all studied sources have immunophenotype of precursor cells of mesenchymal origin. The MMSC of tendon tissue characterized by a greater capacity for colony formation and proliferation, and lower capacity for directed adipogenic differentiation, than MSCs from bone marrow and adipose tissue.

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Functional characterization of human brown adipose tissue metabolism

Biochemical Journal ◽

10.1042/bcj20190464 ◽

2020 ◽

Vol 477 (7) ◽

pp. 1261-1286 ◽

Cited By ~ 3

Author(s):

Marie Anne Richard ◽

Hannah Pallubinsky ◽

Denis P. Blondin

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Functional Characterization ◽

Human Infants ◽

Positron Emission ◽

Brown Adipose ◽

Treatment Of Obesity ◽

And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

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