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Crandall JP, Wahl RL. Perspectives on Brown Adipose Tissue Imaging: Insights from Preclinical and Clinical Observations from the Last and Current Century. J Nucl Med 2021; 62:34S-43S. [PMID: 34230071 DOI: 10.2967/jnumed.120.246991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/22/2020] [Indexed: 11/16/2022] Open
Abstract
Brown adipose tissue (BAT) was first described in the 16th century, but until late last century had mainly been considered a tissue with the function of nonshivering thermogenesis, maintaining body temperature in key organs in newborns who have high body surface areas relative to their weight and thus marked radiative heat loss. BAT was believed to have substantially disappeared by adulthood. Molecular imaging with 18F-FDG PET and PET combined with CT, as well as imaging with 131I-metaiodobenzylguanidine (MIBG) beginning late last century have shown BAT to be present and active well into adulthood. This review highlights key aspects of BAT biology, early empiric observations misidentifying BAT, pitfalls in image interpretation, and methods to intentionally reduce BAT uptake, and outlines multiple imaging methods used to identify BAT in vivo. The therapeutic potential of increasing the amount or activity of BAT for weight loss and improvement of glucose and lipid profiles is highlighted as a major opportunity. Molecular imaging can help dissect the physiology of this complex dynamic tissue and offers the potential for addressing challenges separating "active BAT" from "total BAT." Research in BAT has grown extensively, and 18F-FDG PET is the key imaging procedure against which all other BAT imaging methods must be compared. Given the multiple functions of BAT, it is reasonable to consider it a previously unrecognized endocrine tissue and thus an appropriate topic for review in this supplement to The Journal of Nuclear Medicine.
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Affiliation(s)
- John P Crandall
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Richard L Wahl
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
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Functional characterization of human brown adipose tissue metabolism. Biochem J 2020; 477:1261-1286. [PMID: 32271883 DOI: 10.1042/bcj20190464] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 02/07/2023]
Abstract
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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Yu Q, Huang S, Xu TT, Wang YC, Ju S. Measuring Brown Fat Using MRI and Implications in the Metabolic Syndrome. J Magn Reson Imaging 2020; 54:1377-1392. [PMID: 33047448 DOI: 10.1002/jmri.27340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 08/07/2020] [Accepted: 08/07/2020] [Indexed: 01/04/2023] Open
Abstract
Metabolic syndrome is presently becoming a global health concern. Brown adipose tissue (BAT) has the potential for managing the risk factors of metabolic syndrome by adjusting plasma lipids and glucose. Magnetic resonance imaging (MRI) is a noninvasive and radiation-free imaging modality for BAT research and clinical applications in both animals and humans. In the past decade, MRI technologies for detecting and characterizing BAT have developed rapidly, with progress in MRI sequencing and the emerging understanding of BAT. In this review, we focus on the main MRI methods for BAT including currently used imaging techniques and new methods and their implications for the symptoms and complications of metabolic syndrome. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 2.
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Affiliation(s)
- Qian Yu
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China
| | - Shan Huang
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China
| | - Ting-Ting Xu
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China
| | - Yuan-Cheng Wang
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China
| | - Shenghong Ju
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China
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Peng XG, Zhao Z, Chang D, Bai Y, Xu Q, Ju S. Quantification of Fat Concentration and Vascular Response in Brown and White Adipose Tissue of Rats by Spectral CT Imaging. Korean J Radiol 2020; 21:248-256. [PMID: 31997600 PMCID: PMC6992445 DOI: 10.3348/kjr.2019.0111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 09/23/2019] [Indexed: 11/15/2022] Open
Abstract
Objective The purpose of the study was to non-invasively characterize and discriminate brown adipose tissue (BAT) from white adipose tissue (WAT) in rats using spectral computed tomography (CT) with histological validation. Materials and Methods A lipid-containing phantom (lipid fractions from 0% to 100%) was imaged with spectral CT. An in vivo, non-enhanced spectral CT scan was performed on 24 rats, and fat concentrations of BAT and WAT were measured. The rats were randomized to receive intraperitoneal treatment with norepinephrine (NE) (n = 12) or saline (n = 12). Non-enhanced and enhanced spectral CT scans were performed after treatment to measure the elevation of iodine in BAT and WAT. The BAT/aorta and WAT/aorta ratios were calculated and compared, after which isolated BAT and WAT samples were subjected to histological and uncoupling protein 1 (UCP1) analyses. Results The ex-vivo phantom study showed excellent linear fit between measured fat concentration and the known gravimetric reference standard (r2 = 0.996). In vivo, BAT had significantly lower fat concentration than WAT (p < 0.001). Compared to the saline group, the iodine concentration of BAT increased significantly (p < 0.001) after injection of NE, while the iodine concentration of WAT only changed slightly. The BAT/aorta ratio also increased significantly after exposure to NE compared to the saline group (p < 0.001). Histological and UCP1 expression analyses supported the spectral CT imaging results. Conclusion The study consolidates spectral CT as a new approach for non-invasive imaging of BAT and WAT. Quantitative analyses of BAT and WAT by spectral CT revealed different characteristics and pharmacologic activations in the two types of adipose tissue.
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Affiliation(s)
- Xin Gui Peng
- Department of Radiology, Zhongda Hospital, Jiangsu Key Laboratory of Molecular and Functional Imaging, Medical School of Southeast University, Nanjing, China
| | - Zhen Zhao
- Department of Radiology, Zhongda Hospital, Jiangsu Key Laboratory of Molecular and Functional Imaging, Medical School of Southeast University, Nanjing, China
| | - Di Chang
- Department of Radiology, Zhongda Hospital, Jiangsu Key Laboratory of Molecular and Functional Imaging, Medical School of Southeast University, Nanjing, China
| | - Yingying Bai
- Department of Radiology, Zhongda Hospital, Jiangsu Key Laboratory of Molecular and Functional Imaging, Medical School of Southeast University, Nanjing, China
| | - Qiuzhen Xu
- Department of Radiology, Zhongda Hospital, Jiangsu Key Laboratory of Molecular and Functional Imaging, Medical School of Southeast University, Nanjing, China
| | - Shenghong Ju
- Department of Radiology, Zhongda Hospital, Jiangsu Key Laboratory of Molecular and Functional Imaging, Medical School of Southeast University, Nanjing, China.
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A novel tracer for in vivo optical imaging of fatty acid metabolism in the heart and brown adipose tissue. Sci Rep 2020; 10:11209. [PMID: 32641756 PMCID: PMC7343860 DOI: 10.1038/s41598-020-68065-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 06/16/2020] [Indexed: 12/04/2022] Open
Abstract
Multiplexed imaging is essential for the evaluation of substrate utilization in metabolically active organs, such as the heart and brown adipose tissue (BAT), where substrate preference changes in pathophysiologic states. Optical imaging provides a useful platform because of its low cost, high throughput and intrinsic ability to perform composite readouts. However, the paucity of probes available for in vivo use has limited optical methods to image substrate metabolism. Here, we present a novel near-infrared (NIR) free fatty acid (FFA) tracer suitable for in vivo imaging of deep tissues such as the heart. Using click chemistry, Alexa Fluor 647 DIBO Alkyne was conjugated to palmitic acid. Mice injected with 0.05 nmol/g bodyweight of the conjugate (AlexaFFA) were subjected to conditions known to increase FFA uptake in the heart (fasting) and BAT [cold exposure and injection with the β3 adrenergic agonist CL 316, 243(CL)]. Organs were subsequently imaged both ex vivo and in vivo to quantify AlexaFFA uptake. The blood kinetics of AlexaFFA followed a two-compartment model with an initial fast compartment half-life of 0.14 h and a subsequent slow compartment half-life of 5.2 h, consistent with reversible protein binding. Ex vivo fluorescence imaging after overnight cold exposure and fasting produced a significant increase in AlexaFFA uptake in the heart (58 ± 12%) and BAT (278 ± 19%) compared to warm/fed animals. In vivo imaging of the heart and BAT after exposure to CL and fasting showed a significant increase in AlexaFFA uptake in the heart (48 ± 20%) and BAT (40 ± 10%) compared to saline-injected/fed mice. We present a novel near-infrared FFA tracer, AlexaFFA, that is suitable for in vivo quantification of FFA metabolism and can be applied in the context of a low cost, high throughput, and multiplexed optical imaging platform.
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Topping GJ, Hundshammer C, Nagel L, Grashei M, Aigner M, Skinner JG, Schulte RF, Schilling F. Acquisition strategies for spatially resolved magnetic resonance detection of hyperpolarized nuclei. MAGMA (NEW YORK, N.Y.) 2020; 33:221-256. [PMID: 31811491 PMCID: PMC7109201 DOI: 10.1007/s10334-019-00807-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/08/2019] [Accepted: 11/21/2019] [Indexed: 12/13/2022]
Abstract
Hyperpolarization is an emerging method in magnetic resonance imaging that allows nuclear spin polarization of gases or liquids to be temporarily enhanced by up to five or six orders of magnitude at clinically relevant field strengths and administered at high concentration to a subject at the time of measurement. This transient gain in signal has enabled the non-invasive detection and imaging of gas ventilation and diffusion in the lungs, perfusion in blood vessels and tissues, and metabolic conversion in cells, animals, and patients. The rapid development of this method is based on advances in polarizer technology, the availability of suitable probe isotopes and molecules, improved MRI hardware and pulse sequence development. Acquisition strategies for hyperpolarized nuclei are not yet standardized and are set up individually at most sites depending on the specific requirements of the probe, the object of interest, and the MRI hardware. This review provides a detailed introduction to spatially resolved detection of hyperpolarized nuclei and summarizes novel and previously established acquisition strategies for different key areas of application.
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Affiliation(s)
- Geoffrey J Topping
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christian Hundshammer
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Luca Nagel
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Martin Grashei
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Maximilian Aigner
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jason G Skinner
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | | | - Franz Schilling
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
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Tay SH, Goh HJ, Govindharajulu P, Cheng J, Camps SG, Haldar S, Velan SS, Sun L, Li Y, Henry CJ, Leow MKS. Brown fat activity determined by infrared thermography and thermogenesis measurement using whole body calorimetry (BRIGHT Study). Physiol Res 2020; 69:85-97. [PMID: 31852199 DOI: 10.33549/physiolres.934190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To assess BAT activity in humans at a population level, infrared thermography (IRT) represents a safe, readily repeatable and affordable alternative to 18F-FDG-PET. Building upon a previously proposed method by our laboratory, we further refined the image computational algorithm to quantify BAT activation in the cervical-supraclavicular (C-SCV) region of healthy young men under thermo-neutral and cold exposure conditions. Additionally, we validated the whole-body calorimeter (WBC) in reliably measuring cold-induced thermogenesis. The temperature gradient between C-SCV-deltoid regions, and the corresponding difference in heat power output, increased upon cold air exposure relative to thermo-neutral conditions (by 74.88 %, p<0.0001; and by 71.34 %, p<0.0001 respectively). Resting and cumulative energy expenditure (EE) rose significantly (by 13.14 % and 9.12 % respectively, p=0.0001) while positive correlations between IRT measures and EE were found with cold air exposure (percentage change in heat power gradient between ROI and deltoid, cold air: r(2)=0.29, p=0.026, Pearson's correlation). IRT and WBC can be used to study BAT activation. The refined algorithm allows for more automation and objectivity in IRT data analysis, especially under cold air exposures.
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Affiliation(s)
- S H Tay
- Clinical Nutrition Research Centre, Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore.
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Riis-Vestergaard MJ, Laustsen C, Mariager CØ, Schulte RF, Pedersen SB, Richelsen B. Glucose metabolism in brown adipose tissue determined by deuterium metabolic imaging in rats. Int J Obes (Lond) 2020; 44:1417-1427. [PMID: 31965069 DOI: 10.1038/s41366-020-0533-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 12/13/2019] [Accepted: 01/07/2020] [Indexed: 01/02/2023]
Abstract
BACKGROUND/OBJECTIVES Brown adipose tissue (BAT) has gained growing interest as a potential target for treatment of obesity. Currently, the most widely used technique/method for in vivo measurements of BAT activity in humans is 18FDG PET/CT. To supplement these investigations novel radiation-free methods are warranted. Deuterium metabolic imaging (DMI) is a novel modality that combines magnetic resonance spectroscopic (MRS) imaging with deuterium-labelled glucose (2H-glucose). This allows for spatio-temporal and metabolic imaging beyond glucose uptake. We aimed to evaluate if DMI could discriminate glucose metabolism in BAT of cold-acclimatised and thermoneutral rats. SUBJECTS/METHODS Male Sprague-Dawley rats were housed in a cold environment (9 °C, n = 10) or at thermoneutrality (30 °C, n = 11) for 1 week. For imaging rats were anaesthetized, received a 2H-glucose (1 M, 1.95 g/kg) bolus and DMI was acquired at baseline followed by 20 min time intervals up to 2 h. Furthermore, Dixon MRI was performed for anatomical determination of the interscapular BAT (iBAT) depot along with dynamic contrast enhanced (DCE) MRI to evaluate perfusion. RESULTS 2H-glucose signal was higher in cold-acclimatised rats compared with thermoneutral rats (p ≤ 0.001) indicating an overall increase in glucose uptake and metabolism. This was in line with a lower fat/water threshold, higher perfusion and increased UCP1 mRNA expression in iBAT (ninefold increment) of cold-acclimatised rats compared with thermoneutral rats. CONCLUSIONS We find that DMI can discriminate cold-acclimatised and thermoneutral BAT in rats. This is the first study to evaluate BAT activity by DMI, which may open up for the use of the non-radioactive DMI method for BAT measurements in humans.
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Affiliation(s)
- Mette Ji Riis-Vestergaard
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle Juul Jensens Boulevard 99, 8200, Aarhus N, Denmark. .,Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - Christoffer Laustsen
- MR Research Center, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | | | - Steen Bønløkke Pedersen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle Juul Jensens Boulevard 99, 8200, Aarhus N, Denmark.,Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Steno Diabetes Center Aarhus, Aarhus, Denmark
| | - Bjørn Richelsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle Juul Jensens Boulevard 99, 8200, Aarhus N, Denmark.,Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Steno Diabetes Center Aarhus, Aarhus, Denmark
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Wu M, Junker D, Branca RT, Karampinos DC. Magnetic Resonance Imaging Techniques for Brown Adipose Tissue Detection. Front Endocrinol (Lausanne) 2020; 11:421. [PMID: 32849257 PMCID: PMC7426399 DOI: 10.3389/fendo.2020.00421] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/27/2020] [Indexed: 12/11/2022] Open
Abstract
Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) methods can non-invasively assess brown adipose tissue (BAT) structure and function. Recently, MRI and MRS have been proposed as a means to differentiate BAT from white adipose tissue (WAT) and to extract morphological and functional information on BAT inaccessible by other means. Specifically, proton MR (1H) techniques, such as proton density fat fraction mapping, diffusion imaging, and intermolecular multiple quantum coherence imaging, have been employed to access BAT microstructure; MR thermometry, relaxometry, and MRI and MRS with 31P, 2H, 13C, and 129Xe have shown to provide complementary information on BAT function. The purpose of the present review is to provide a comprehensive overview of MR imaging and spectroscopy techniques used to detect BAT in rodents and in humans. The present work discusses common challenges of current methods and provides an outlook on possible future directions of using MRI and MRS in BAT studies.
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Affiliation(s)
- Mingming Wu
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany
- *Correspondence: Mingming Wu
| | - Daniela Junker
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Rosa Tamara Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Dimitrios C. Karampinos
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany
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Frankl J, Sherwood A, Clegg DJ, Scherer PE, Öz OK. Imaging Metabolically Active Fat: A Literature Review and Mechanistic Insights. Int J Mol Sci 2019; 20:ijms20215509. [PMID: 31694216 PMCID: PMC6862590 DOI: 10.3390/ijms20215509] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/01/2019] [Accepted: 11/01/2019] [Indexed: 02/07/2023] Open
Abstract
Currently, obesity is one of the leading causes death in the world. Shortly before 2000, researchers began describing metabolically active adipose tissue on cancer-surveillance 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in adult humans. This tissue generates heat through mitochondrial uncoupling and functions similar to classical brown and beige adipose tissue in mice. Despite extensive research, human brown/beige fat's role in resistance to obesity in humans has not yet been fully delineated. FDG uptake is the de facto gold standard imaging technique when studying brown adipose tissue, although it has not been rigorously compared to other techniques. We, therefore, present a concise review of established and emerging methods to image brown adipose tissue activity in humans. Reviewed modalities include anatomic imaging with CT and magnetic resonance imaging (MRI); molecular imaging with FDG, fatty acids, and acetate; and emerging techniques. FDG-PET/CT is the most commonly used modality because of its widespread use in cancer imaging, but there are mechanistic reasons to believe other radiotracers may be more sensitive and accurate at detecting brown adipose tissue activity. Radiation-free modalities may help the longitudinal study of brown adipose tissue activity in the future.
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Affiliation(s)
- Joseph Frankl
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA; (J.F.); (A.S.)
| | - Amber Sherwood
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA; (J.F.); (A.S.)
| | - Deborah J. Clegg
- College of Nursing and Health Professions, Drexel University, 10th Floor, Room 1092, 1601 Cherry Street, Mail Stop 10501, Philadelphia, PA 19102, USA;
| | - Philipp E. Scherer
- Department of Internal Medicine, Touchstone Diabetes Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA;
| | - Orhan K. Öz
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA; (J.F.); (A.S.)
- Correspondence:
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Karampinos DC, Weidlich D, Wu M, Hu HH, Franz D. Techniques and Applications of Magnetic Resonance Imaging for Studying Brown Adipose Tissue Morphometry and Function. Handb Exp Pharmacol 2019; 251:299-324. [PMID: 30099625 DOI: 10.1007/164_2018_158] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The present review reports on the current knowledge and recent findings in magnetic resonance imaging (MRI) and spectroscopy (MRS) of brown adipose tissue (BAT). The work summarizes the features and mechanisms that allow MRI to differentiate BAT from white adipose tissue (WAT) by making use of their distinct morphological appearance and the functional characteristics of BAT. MR is a versatile imaging modality with multiple contrast mechanisms as potential candidates in the study of BAT, targeting properties of 1H, 13C, or 129Xe nuclei. Techniques for assessing BAT morphometry based on fat fraction and markers of BAT microstructure, including intermolecular quantum coherence and diffusion imaging, are first described. Techniques for assessing BAT function based on the measurement of BAT metabolic activity, perfusion, oxygenation, and temperature are then presented. The application of the above methods in studies of BAT in animals and humans is described, and future directions in MR study of BAT are finally discussed.
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Affiliation(s)
- Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
| | - Dominik Weidlich
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Mingming Wu
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Houchun H Hu
- Department of Radiology, Nationwide Children's Hospital, Columbus, OH, USA
| | - Daniela Franz
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
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12
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Jing Y, Niu Y, Liu C, Zen K, Li D. In silico identification of lipid-binding α helices of uncoupling protein 1. Biomed Rep 2018; 9:313-317. [PMID: 30233783 PMCID: PMC6142039 DOI: 10.3892/br.2018.1133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/19/2018] [Indexed: 11/29/2022] Open
Abstract
Uncoupling protein 1 (UCP1) located at the mitochondrial inner membrane serves an important role in adaptive non-shivering thermogenesis. Previous data has demonstrated that membrane lipids regulate the biological functions of membrane proteins. However, how mitochondrial lipids interact with UCP1 still remains elusive. In this study, the interactions between UCP1 and membrane lipids were investigated, using bioinformatic approaches due to the limitations associated with experimental techniques. A total of 8 UCP1 peptide regions with α-helices were identified and related to functional sites of UCP1. These were all novel peptide sequences compared with the known protein-lipid interactions. Among several types of UCP1-binding molecules, cardiolipin appeared to serve as a key interacting molecule of the 8 lipid-binding α-helix regions of UCP1. Two cardiolipin-binding lysines (K175 and K269) of UCP1 may be crucial for this UCP1-cardiolipin recognition and UCP1 function. The present findings provide novel insight into the associations of UCP1 with lipids and the potential drug targets in UCP1-associated diseases.
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Affiliation(s)
- Ying Jing
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Yahan Niu
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Chang Liu
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Ke Zen
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Donghai Li
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
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Riis-Vestergaard MJ, Breining P, Pedersen SB, Laustsen C, Stødkilde-Jørgensen H, Borghammer P, Jessen N, Richelsen B. Evaluation of Active Brown Adipose Tissue by the Use of Hyperpolarized [1- 13C]Pyruvate MRI in Mice. Int J Mol Sci 2018; 19:ijms19092597. [PMID: 30200469 PMCID: PMC6164296 DOI: 10.3390/ijms19092597] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/21/2018] [Accepted: 08/30/2018] [Indexed: 02/07/2023] Open
Abstract
The capacity to increase energy expenditure makes brown adipose tissue (BAT) a putative target for treatment of metabolic diseases such as obesity. Presently, investigation of BAT in vivo is mainly performed by fluoro-d-glucose positron emission tomography (FDG PET)/CT. However, non-radioactive methods that add information on, for example, substrate metabolism are warranted. Thus, the aim of this study was to evaluate the potential of hyperpolarized [1-13C]pyruvate Magnetic Resonance Imaging (HP-MRI) to determine BAT activity in mice following chronic cold exposure. Cold (6 °C) and thermo-neutral (30 °C) acclimated mice were scanned with HP-MRI for assessment of the interscapular BAT (iBAT) activity. Comparable mice were scanned with the conventional method FDG PET/MRI. Finally, iBAT was evaluated for gene expression and protein levels of the specific thermogenic marker, uncoupling protein 1 (UCP1). Cold exposure increased the thermogenic capacity 3–4 fold (p < 0.05) as measured by UCP1 gene and protein analysis. Furthermore, cold exposure as compared with thermo-neutrality increased iBAT pyruvate metabolism by 5.5-fold determined by HP-MRI which is in good agreement with the 5-fold increment in FDG uptake (p < 0.05) measured by FDG PET/MRI. iBAT activity is detectable in mice using HP-MRI in which potential changes in intracellular metabolism may add useful information to the conventional FDG PET studies. HP-MRI may also be a promising radiation-free tool for repetitive BAT studies in humans.
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Affiliation(s)
- Mette Ji Riis-Vestergaard
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark.
- Institute of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark.
| | - Peter Breining
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark.
- Institute of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark.
| | - Steen Bønløkke Pedersen
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark.
- Institute of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark.
| | - Christoffer Laustsen
- MR Research Center, Institute of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark.
| | | | - Per Borghammer
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, 8000 Aarhus C, Denmark.
| | - Niels Jessen
- Department of Clinical Pharmacology, Aarhus University Hospital, 8000 Aarhus C, Denmark.
| | - Bjørn Richelsen
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark.
- Institute of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark.
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14
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Chondronikola M, Beeman SC, Wahl RL. Non-invasive methods for the assessment of brown adipose tissue in humans. J Physiol 2018; 596:363-378. [PMID: 29119565 PMCID: PMC5792561 DOI: 10.1113/jp274255] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/04/2017] [Indexed: 01/10/2023] Open
Abstract
Brown adipose tissue (BAT) is a recently rediscovered tissue in people that has shown promise as a potential therapeutic target against obesity and its metabolic abnormalities. Reliable non-invasive assessment of BAT volume and activity is critical to allow its importance in metabolic control to be evaluated. Positron emission tomography/computed tomography (PET/CT) in combination with 2-deoxy-2-[18 F]fluoroglucose administration is currently the most frequently used and most established method for the detection and quantification of activated BAT in humans. However, it involves radiation exposure and can detect activated (e.g. after cold exposure), but not quiescent, BAT. Several alternative methods that overcome some of these limitations have been developed including different PET approaches, single-photon emission imaging, CT, magnetic resonance based approaches, contrast-enhanced ultrasound, near infrared spectroscopy, and temperature assessment of fat depots containing brown adipocytes. The purpose of this review is to summarize and critically evaluate the currently available methods that non-invasively probe various aspects of BAT biology in order to assess BAT volume and/or metabolism. Although several of these methods show promise for the non-invasive assessment of BAT volume and function, further research is needed to optimize them to enable an accurate, reproducible and practical means for the assessment of human BAT content and its metabolic function.
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Affiliation(s)
- Maria Chondronikola
- Center for Human NutritionWashington University School of MedicineSt LouisMOUSA
- Harokopio University of AthensAthensGreece
| | - Scott C. Beeman
- Department of Radiology, Mallinckrodt Institute of RadiologyWashington University School of MedicineSt LouisMOUSA
| | - Richard L. Wahl
- Department of Radiology, Mallinckrodt Institute of RadiologyWashington University School of MedicineSt LouisMOUSA
- Department of Radiation Oncology, Mallinckrodt Institute of RadiologyWashington University School of MedicineSt LouisMOUSA
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15
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Human brown adipose tissue-function and therapeutic potential in metabolic disease. Curr Opin Pharmacol 2017; 37:1-9. [PMID: 28800407 DOI: 10.1016/j.coph.2017.07.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 07/20/2017] [Indexed: 12/22/2022]
Abstract
There has been a resurgence of interest in brown adipose tissue (BAT) over the last decade. Key to this has been our ability to accurately image it, which has improved significantly. The role of BAT in regulating energy expenditure is important, and its pharmacological manipulation may hold therapeutic potential in metabolic disease. There is ample evidence of BAT activation by cold exposure, and pharmacological utilisation of similar pathways, using B3 receptor agonists holds promise since the development of selective agonists with limited cross-reactivity has rekindled interest. Endogenous agents like irisin, FGF21 and certain gut hormones may hold value as BAT activators. Other agents such as steroid hormones may also hold therapeutic potential, although short-term worsening of metabolic profile remains problematic. Clearly, pharmacological manipulation of BAT is important, and thanks to recent advances we may one day be able to add such agents to our anti-obesity arsenal.
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16
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Sampath SC, Sampath SC, Bredella MA, Cypess AM, Torriani M. Imaging of Brown Adipose Tissue: State of the Art. Radiology 2017; 280:4-19. [PMID: 27322970 DOI: 10.1148/radiol.2016150390] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The rates of diabetes, obesity, and metabolic disease have reached epidemic proportions worldwide. In recent years there has been renewed interest in combating these diseases not only by modifying energy intake and lifestyle factors, but also by inducing endogenous energy expenditure. This approach has largely been stimulated by the recent recognition that brown adipose tissue (BAT)-long known to promote heat production and energy expenditure in infants and hibernating mammals-also exists in adult humans. This landmark finding relied on the use of clinical fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography, and imaging techniques continue to play a crucial and increasingly central role in understanding BAT physiology and function. Herein, the authors review the origins of BAT imaging, discuss current preclinical and clinical strategies for imaging BAT, and discuss imaging methods that will provide crucial insight into metabolic disease and how it may be treated by modulating BAT activity. (©) RSNA, 2016.
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Affiliation(s)
- Srihari C Sampath
- From Musculoskeletal Biology and Bioimaging, Department of Pharmacology, Genomics Institute of the Novartis Research Foundation, San Diego, Calif (Srihari Sampath, Srinath Sampath); Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114 (M.B., M.T.); and Translational Physiology Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Md (A.M.C.)
| | - Srinath C Sampath
- From Musculoskeletal Biology and Bioimaging, Department of Pharmacology, Genomics Institute of the Novartis Research Foundation, San Diego, Calif (Srihari Sampath, Srinath Sampath); Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114 (M.B., M.T.); and Translational Physiology Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Md (A.M.C.)
| | - Miriam A Bredella
- From Musculoskeletal Biology and Bioimaging, Department of Pharmacology, Genomics Institute of the Novartis Research Foundation, San Diego, Calif (Srihari Sampath, Srinath Sampath); Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114 (M.B., M.T.); and Translational Physiology Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Md (A.M.C.)
| | - Aaron M Cypess
- From Musculoskeletal Biology and Bioimaging, Department of Pharmacology, Genomics Institute of the Novartis Research Foundation, San Diego, Calif (Srihari Sampath, Srinath Sampath); Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114 (M.B., M.T.); and Translational Physiology Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Md (A.M.C.)
| | - Martin Torriani
- From Musculoskeletal Biology and Bioimaging, Department of Pharmacology, Genomics Institute of the Novartis Research Foundation, San Diego, Calif (Srihari Sampath, Srinath Sampath); Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114 (M.B., M.T.); and Translational Physiology Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Md (A.M.C.)
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17
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El Hadi H, Vettor R, Rossato M. Functional imaging of brown adipose tissue in human. Horm Mol Biol Clin Investig 2017; 31:hmbci-2017-0009. [PMID: 28609290 DOI: 10.1515/hmbci-2017-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/02/2017] [Indexed: 11/15/2022]
Abstract
Obesity has become a major public health challenge and an increasing trend is seen in its prevalence worldwide. It is a complex disorder involving an excessive amount of body fat as a result of an energy imbalance leading to caloric overload. Since the discovery of functional brown adipose tissue (BAT) in adult humans, with energy dissipating properties, this thermogenic tissue has thus emerged as an attractive therapeutic target to combat obesity and related cardiometabolic disorders. The advancements in imaging modalities to evaluate organ-specific metabolism in humans is substantially contributing to understand the physiological role of BAT. This review presents an overview of the different imaging approaches implied in BAT assessment, with a special emphasis on adult human BAT. In this context, we also attempted to summarize the developmental origins and physiology of BAT.
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Affiliation(s)
- Hamza El Hadi
- Internal Medicine 3, Department of Medicine - DIMED, University of Padova, Padova 35128, Italy
| | - Roberto Vettor
- Internal Medicine 3, Department of Medicine - DIMED, University of Padova, Padova 35128, Italy
| | - Marco Rossato
- Internal Medicine 3, Department of Medicine - DIMED, University of Padova, Via Giustiniani 2, Padova 35128, Italy, Phone: +39 049 8218747, Fax: +39 049 8213332
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18
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Imaging oxygen metabolism with hyperpolarized magnetic resonance: a novel approach for the examination of cardiac and renal function. Biosci Rep 2017; 37:BSR20160186. [PMID: 27899435 PMCID: PMC5270319 DOI: 10.1042/bsr20160186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 12/24/2022] Open
Abstract
Every tissue in the body critically depends on meeting its energetic demands with sufficient oxygen supply. Oxygen supply/demand imbalances underlie the diseases that inflict the greatest socio-economic burden globally. The purpose of this review is to examine how hyperpolarized contrast media, used in combination with MR data acquisition methods, may advance our ability to assess oxygen metabolism non-invasively and thus improve management of clinical disease. We first introduce the concept of hyperpolarization and how hyperpolarized contrast media have been practically implemented to achieve translational and clinical research. We will then analyse how incorporating hyperpolarized contrast media could enable realization of unmet technical needs in clinical practice. We will focus on imaging cardiac and renal oxygen metabolism, as both organs have unique physiological demands to satisfy their requirements for tissue oxygenation, their dysfunction plays a fundamental role in society’s most prevalent diseases, and each organ presents unique imaging challenges. It is our aim that this review attracts a multi-disciplinary audience and sparks collaborations that utilize an exciting, emergent technology to advance our ability to treat patients adversely affected by an oxygen supply/demand mismatch.
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19
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McCallister A, Zhang L, Burant A, Katz L, Branca RT. A pilot study on the correlation between fat fraction values and glucose uptake values in supraclavicular fat by simultaneous PET/MRI. Magn Reson Med 2017; 78:1922-1932. [PMID: 28112821 DOI: 10.1002/mrm.26589] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/15/2016] [Accepted: 12/01/2016] [Indexed: 01/02/2023]
Abstract
PURPOSE To assess the spatial correlation between MRI and 18F-fludeoxyglucose positron emission tomography (FDG-PET) maps of human brown adipose tissue (BAT) and to measure differences in fat fraction (FF) between glucose avid and non-avid regions of the supraclavicular fat depot using a hybrid FDG-PET/MR scanner. METHODS In 16 healthy volunteers, mean age of 30 and body mass index of 26, FF, R2*, and FDG uptake maps were acquired simultaneously using a hybrid PET/MR system while employing an individualized cooling protocol to maximally stimulate BAT. RESULTS Fourteen of the 16 volunteers reported BAT-positive FDG-PET scans. MR FF maps of BAT correlate well with combined FDG-PET/MR maps of BAT only in subjects with intense glucose uptake. The results indicate that the extent of the spatial correlation positively correlates with maximum FDG uptake in the supraclavicular fat depot. No consistent, significant differences were found in FF or R2* between FDG avid and non-avid supraclavicular fat regions. In a few FDG-positive subjects, a small but significant linear decrease in BAT FF was observed during BAT stimulation. CONCLUSION MR FF, when used in conjunction with FDG uptake maps, can be seen as a valuable, radiation-free alternative to CT and can be used to measure tissue hydration and lipid consumption in some subjects. Magn Reson Med 78:1922-1932, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Andrew McCallister
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Le Zhang
- Department of Applied Physical Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Alex Burant
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Laurence Katz
- Department of Emergency Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Rosa Tamara Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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20
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Hui SC, Ko JK, Zhang T, Shi L, Yeung DK, Wang D, Chan Q, Chu WC. Quantification of brown and white adipose tissue based on Gaussian mixture model using water-fat and T2* MRI in adolescents. J Magn Reson Imaging 2017; 46:758-768. [DOI: 10.1002/jmri.25632] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/22/2016] [Indexed: 01/03/2023] Open
Affiliation(s)
- Steve C.N. Hui
- Department of Imaging and Interventional Radiology; Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
| | - Jacky K.L. Ko
- Department of Imaging and Interventional Radiology; Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
| | - Teng Zhang
- Department of Imaging and Interventional Radiology; Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
| | - Lin Shi
- Department of Medicine and Therapeutics; Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
- Chow Yuk Ho Technology Centre for Innovative Medicine, Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
| | - David K.W. Yeung
- Department of Imaging and Interventional Radiology; Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
| | - Defeng Wang
- Department of Imaging and Interventional Radiology; Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
- Research Center for Medical Image Computing, Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
| | - Queenie Chan
- Philips Healthcare; Sha Tin, New Territories Hong Kong SAR
| | - Winnie C.W. Chu
- Department of Imaging and Interventional Radiology; Chinese University of Hong Kong; Sha Tin, New Territories Hong Kong SAR
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21
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Aboualizadeh E, Carmichael OT, He P, Albarado DC, Morrison CD, Hirschmugl CJ. Quantifying Biochemical Alterations in Brown and Subcutaneous White Adipose Tissues of Mice Using Fourier Transform Infrared Widefield Imaging. Front Endocrinol (Lausanne) 2017; 8:121. [PMID: 28620356 PMCID: PMC5450226 DOI: 10.3389/fendo.2017.00121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/17/2017] [Indexed: 01/08/2023] Open
Abstract
Stimulating increased thermogenic activity in adipose tissue is an important biological target for obesity treatment, and label-free imaging techniques with the potential to quantify stimulation-associated biochemical changes to the adipose tissue are highly sought after. In this study, we used spatially resolved Fourier transform infrared (FTIR) imaging to quantify biochemical changes caused by cold exposure in the brown and subcutaneous white adipose tissues (BAT and s-WAT) of 6 week-old C57BL6 mice exposed to 30°C (N = 5), 24°C (N = 5), and 10°C (N = 5) conditions for 10 days. Fat exposed to colder temperatures demonstrated greater thermogenic activity as indicated by increased messenger RNA expression levels of a panel of thermogenic marker genes including uncoupling protein 1 (UCP-1) and Dio2. Protein to lipid ratio, calculated from the ratio of the integrated area from 1,600 to 1,700 cm-1 (amide I) to the integrated area from 2,830 to 2,980 cm-1 (saturated lipids), was elevated in 10°C BAT and s-WAT compared to 24°C (p = 0.004 and p < 0.0001) and 30°C (p = 0.0033 and p < 0.0001). Greater protein to lipid ratio was associated with greater UCP-1 expression level in the BAT (p = 0.021) and s-WAT (p = 0.032) and greater Dio2 expression in s-WAT (p = 0.033). The degree of unsaturation, calculated from the ratio of the integrated area from 2,992 to 3,020 cm-1 (unsaturated lipids) to the integrated area from 2,830 to 2,980 cm-1 (saturated lipids), showed stepwise decreases going from colder-exposed to warmer-exposed BAT. Complementary 1H NMR measurements confirmed the findings from this ratio in BAT. Principal component analysis applied to FTIR spectra revealed pronounced differences in overall spectral characteristics between 30, 24, and 10°C BAT and s-WAT. Spatially resolved FTIR imaging is a promising technique to quantify cold-induced biochemical changes in BAT and s-WAT in a label-free manner.
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Affiliation(s)
- Ebrahim Aboualizadeh
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | | | - Ping He
- Pennington Biomedical Research Center, Baton Rouge, LA, United States
| | - Diana C. Albarado
- Pennington Biomedical Research Center, Baton Rouge, LA, United States
| | | | - Carol J. Hirschmugl
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
- *Correspondence: Carol J. Hirschmugl,
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22
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Marzola P, Boschi F, Moneta F, Sbarbati A, Zancanaro C. Preclinical In vivo Imaging for Fat Tissue Identification, Quantification, and Functional Characterization. Front Pharmacol 2016; 7:336. [PMID: 27725802 PMCID: PMC5035738 DOI: 10.3389/fphar.2016.00336] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/12/2016] [Indexed: 12/31/2022] Open
Abstract
Localization, differentiation, and quantitative assessment of fat tissues have always collected the interest of researchers. Nowadays, these topics are even more relevant as obesity (the excess of fat tissue) is considered a real pathology requiring in some cases pharmacological and surgical approaches. Several weight loss medications, acting either on the metabolism or on the central nervous system, are currently under preclinical or clinical investigation. Animal models of obesity have been developed and are widely used in pharmaceutical research. The assessment of candidate drugs in animal models requires non-invasive methods for longitudinal assessment of efficacy, the main outcome being the amount of body fat. Fat tissues can be either quantified in the entire animal or localized and measured in selected organs/regions of the body. Fat tissues are characterized by peculiar contrast in several imaging modalities as for example Magnetic Resonance Imaging (MRI) that can distinguish between fat and water protons thank to their different magnetic resonance properties. Since fat tissues have higher carbon/hydrogen content than other soft tissues and bones, they can be easily assessed by Computed Tomography (CT) as well. Interestingly, MRI also discriminates between white and brown adipose tissue (BAT); the latter has long been regarded as a potential target for anti-obesity drugs because of its ability to enhance energy consumption through increased thermogenesis. Positron Emission Tomography (PET) performed with 18F-FDG as glucose analog radiotracer reflects well the metabolic rate in body tissues and consequently is the technique of choice for studies of BAT metabolism. This review will focus on the main, non-invasive imaging techniques (MRI, CT, and PET) that are fundamental for the assessment, quantification and functional characterization of fat deposits in small laboratory animals. The contribution of optical techniques, which are currently regarded with increasing interest, will be also briefly described. For each technique the physical principles of signal detection will be overviewed and some relevant studies will be summarized. Far from being exhaustive, this review has the purpose to highlight some strategies that can be adopted for the in vivo identification, quantification, and functional characterization of adipose tissues mainly from the point of view of biophysics and physiology.
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Affiliation(s)
- Pasquina Marzola
- Department of Computer Science, University of Verona, VeronaItaly
| | - Federico Boschi
- Department of Computer Science, University of Verona, VeronaItaly
| | - Francesco Moneta
- Preclinical Imaging Division – Bruker BioSpin, Bruker Italia s.r.l, MilanoItaly
| | - Andrea Sbarbati
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, VeronaItaly
| | - Carlo Zancanaro
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, VeronaItaly
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23
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Abstract
The demonstration of the presence of metabolically active brown adipose tissue (BAT) in adult humans using positron emission tomography (PET) over the past decade has lead to the rapid development of our knowledge regarding the role of BAT in energy metabolism in animal models and in humans. Although animal models continue to provide highly valuable information regarding the mechanisms regulating BAT development, mass and metabolic functions, these studies led to many assumptions that have been at best only partially verified in humans so far. Combined to some limitations of the current investigation approaches used in humans, this has lead to speculation on the potential role of BAT dysfunction in the development of cardiometabolic disorders and on the potential of BAT metabolic activation to treat these conditions. Here we propose a critical review of the evidence for the implication of BAT in cardiometabolic health.
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Affiliation(s)
- Denis P Blondin
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - André C Carpentier
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada.
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Wang JX, Merritt ME, Sherry D, Malloy CR. A general chemical shift decomposition method for hyperpolarized (13) C metabolite magnetic resonance imaging. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:665-73. [PMID: 27060361 PMCID: PMC5022286 DOI: 10.1002/mrc.4435] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 02/08/2016] [Accepted: 02/29/2016] [Indexed: 05/26/2023]
Abstract
Metabolic imaging with hyperpolarized carbon-13 allows sequential steps of metabolism to be detected in vivo. Potential applications in cancer, brain, muscular, myocardial, and hepatic metabolism suggest that clinical applications could be readily developed. A primary concern in imaging hyperpolarized nuclei is the irreversible decay of the enhanced magnetization back to thermal equilibrium. Multiple methods for rapid imaging of hyperpolarized substrates and their products have been proposed with a multi-point Dixon method distinguishing itself as a robust protocol for imaging [1-(13) C]pyruvate. We describe here a generalized chemical shift decomposition method that incorporates a single-shot spiral imaging sequence plus a spectroscopic sequence to retain as much spin polarization as possible while allowing detection of metabolites that have a wide range of chemical shift values. The new method is demonstrated for hyperpolarized [1-(13) C]pyruvate, [1-(13) C]acetoacetate, and [2-(13) C]dihydroxyacetone. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jian-xiong Wang
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Matthew E. Merritt
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Craig R. Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
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25
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Heymsfield SB, Hu HH, Shen W, Carmichael O. Emerging Technologies and their Applications in Lipid Compartment Measurement. Trends Endocrinol Metab 2015; 26:688-698. [PMID: 26596676 PMCID: PMC4673021 DOI: 10.1016/j.tem.2015.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/19/2015] [Accepted: 10/19/2015] [Indexed: 12/22/2022]
Abstract
Non-Communicable diseases (NCDs), including obesity, are emerging as the major health concern of the 21st century. Excess adiposity and related NCD metabolic disturbances have stimulated development of new lipid compartment measurement technologies to help us to understand cellular energy exchange, to refine phenotypes, and to develop predictive markers of adverse clinical outcomes. Recent advances now allow quantification of multiple intracellular lipid and adipose tissue compartments that can be evaluated across the human lifespan. With magnetic resonance methods leading the way, newer approaches will give molecular structural and metabolic information beyond the laboratory in real-world settings. The union between these new technologies and the growing NCD population is creating an exciting interface in advancing our understanding of chronic disease mechanisms.
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Affiliation(s)
- Steven B Heymsfield
- Pennington Biomedical Research Center, Louisiana State University (LSU) System, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
| | - Houchun Harry Hu
- Phoenix Children's Hospital, Department of Radiology, 1919 East Thomas Road, Phoenix, AZ 85016, USA
| | - Wei Shen
- New York Obesity Research Center, Department of Pediatrics and Institute of Human Nutrition, Columbia University, New York, NY 10032, USA
| | - Owen Carmichael
- Pennington Biomedical Research Center, Louisiana State University (LSU) System, 6400 Perkins Road, Baton Rouge, LA 70808, USA
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Rice DR, White AG, Leevy WM, Smith BD. Fluorescence Imaging of Interscapular Brown Adipose Tissue in Living Mice. J Mater Chem B 2015; 3:1979-1989. [PMID: 26015867 DOI: 10.1039/c4tb01914h] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Brown adipose tissue (BAT) plays a key role in energy expenditure and heat generation and is a promising target for diagnosing and treating obesity, diabetes and related metabolism disorders. While several nuclear and magnetic resonance imaging methods are established for detecting human BAT, there are no convenient protocols for high throughput imaging of BAT in small animal models. Here we disclose a simple but effective method for non-invasive optical imaging of interscapular BAT in mice using a micellar formulation of the commercially available deep-red fluorescent probe, SRFluor680. Whole-body fluorescence imaging of living mice shows extensive accumulation of the fluorescent probe in the interscapular BAT and ex vivo analysis shows 3.5-fold selectivity for interscapular BAT over interscapular WAT. Additional imaging studies indicate that SRFluor680 uptake is independent of mouse species and BAT metabolic state. The results are consistent with an unusual pharmacokinetic process that involves irreversible translocation of the lipophilic SRFluor680 from the micelle nanocarrier into the adipocytes within the BAT. Multimodal PET/CT and planar fluorescence/X-ray imaging of the same living animal shows co-localization of BAT mass signal reported by the fluorescent probe and BAT metabolism signal reported by the PET agent, 18F-FDG. The results indicate a path towards a new, dual probe molecular imaging paradigm that allows separate and independent non-invasive visualization of BAT mass and BAT metabolism in a living subject.
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Affiliation(s)
- Douglas R Rice
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, 46556 IN, USA
| | - Alexander G White
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, 46556 IN, USA
| | - W Matthew Leevy
- Department of Biological Science, Galvin Life Sciences, University of Notre Dame, Notre Dame, 46556 IN, USA
| | - Bradley D Smith
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, 46556 IN, USA
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Izzi-Engbeaya C, Salem V, Atkar RS, Dhillo WS. Insights into Brown Adipose Tissue Physiology as Revealed by Imaging Studies. Adipocyte 2015; 4:1-12. [PMID: 26167397 DOI: 10.4161/21623945.2014.965609] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 12/12/2022] Open
Abstract
There has been resurgence in interest in brown adipose tissue (BAT) following radiological and histological identification of metabolically active BAT in adult humans. Imaging enables BAT to be studied non-invasively and therefore imaging studies have contributed a significant amount to what is known about BAT function in humans. In this review the current knowledge (derived from imaging studies) about the prevalence, function, activity and regulation of BAT in humans (as well as relevant rodent studies), will be summarized.
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Key Words
- 11C-MHED, [11C]-meta-hydroxyephedrine
- 18F-FDG, [18F]-fluorodeoxyglucose
- 99mTc-sestamibi, technetium-99m sestamibi
- 99mTc-tetrofosmin, technetium-99m tetrofosmin
- ATP, adenosine triphosphate
- BAT, brown adipose tissue
- BMI, body mass index
- BOLD, blood oxygen level dependent
- CIT, cold-induced thermogenesis
- IQR, interquartile range
- MRI, magnetic resonance imaging
- NST, non-shivering thermogenesis
- PET-CT, positron emission tomography-computed tomography
- SPECT, single photon emission CT
- UCP-1, uncoupling protein 1
- WAT, white adipose tissue
- brown adipose tissue
- energy expenditure
- imaging
- metabolism
- thermogenesis
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Abstract
As part of a current worldwide effort to understand the physiology of human BAT (hBAT) and whether its thermogenic activity can be manipulated to treat obesity, the workshop "Exploring the Roles of Brown Fat in Humans" was convened at the National Institutes of Health on February 25-26, 2014. Presentations and discussion indicated that hBAT and its physiological roles are highly complex, and research is needed to understand the health impact of hBAT beyond thermogenesis and body weight regulation, and to define its interactions with core physiological processes like glucose homeostasis, cachexia, physical activity, bone structure, sleep, and circadian rhythms.
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Affiliation(s)
- Aaron M Cypess
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Carol R Haft
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Maren R Laughlin
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Houchun H Hu
- Department of Radiology, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA
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Crane JD, Mottillo EP, Farncombe TH, Morrison KM, Steinberg GR. A standardized infrared imaging technique that specifically detects UCP1-mediated thermogenesis in vivo. Mol Metab 2014; 3:490-4. [PMID: 24944909 PMCID: PMC4060225 DOI: 10.1016/j.molmet.2014.04.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 01/09/2023] Open
Abstract
The activation and expansion of brown adipose tissue (BAT) has emerged as a promising strategy to counter obesity and the metabolic syndrome by increasing energy expenditure. The subsequent testing and validation of novel agents that augment BAT necessitates accurate pre-clinical measurements in rodents regarding the capacity for BAT-derived thermogenesis. We present a novel method to measure BAT thermogenesis using infrared imaging following β3-adrenoreceptor stimulation in mice. We show that the increased body surface temperature observed using this method is due solely to uncoupling protein-1 (UCP1)-mediated thermogenesis and that this technique is able to discern differences in BAT activity in mice acclimated to 23 °C or thermoneutrality (30 °C). These findings represent the first standardized method utilizing infrared imaging to specifically detect UCP1 activity in vivo.
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Affiliation(s)
- Justin D Crane
- Department of Pediatrics, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada ; Department of Medicine, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada ; Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada
| | - Emilio P Mottillo
- Department of Medicine, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada ; Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada
| | - Troy H Farncombe
- Department of Nuclear Medicine, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada ; Department of Radiology, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada
| | - Katherine M Morrison
- Department of Pediatrics, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada
| | - Gregory R Steinberg
- Department of Medicine, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada ; Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S 4L8, Canada
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30
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Harry H, Kan HE. Quantitative proton MR techniques for measuring fat. NMR IN BIOMEDICINE 2013; 26:1609-29. [PMID: 24123229 PMCID: PMC4001818 DOI: 10.1002/nbm.3025] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 07/13/2013] [Accepted: 08/19/2013] [Indexed: 05/09/2023]
Abstract
Accurate, precise and reliable techniques for the quantification of body and organ fat distributions are important tools in physiology research. They are critically needed in studies of obesity and diseases involving excess fat accumulation. Proton MR methods address this need by providing an array of relaxometry-based (T1, T2) and chemical shift-based approaches. These techniques can generate informative visualizations of regional and whole-body fat distributions, yield measurements of fat volumes within specific body depots and quantify fat accumulation in abdominal organs and muscles. MR methods are commonly used to investigate the role of fat in nutrition and metabolism, to measure the efficacy of short- and long-term dietary and exercise interventions, to study the implications of fat in organ steatosis and muscular dystrophies and to elucidate pathophysiological mechanisms in the context of obesity and its comorbidities. The purpose of this review is to provide a summary of mainstream MR strategies for fat quantification. The article succinctly describes the principles that differentiate water and fat proton signals, summarizes the advantages and limitations of various techniques and offers a few illustrative examples. The article also highlights recent efforts in the MR of brown adipose tissue and concludes by briefly discussing some future research directions.
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Affiliation(s)
- Houchun Harry
- Corresponding Author Houchun Harry Hu, PhD Children's Hospital Los Angeles University of Southern California 4650 Sunset Boulevard Department of Radiology, MS #81 Los Angeles, California, USA. 90027 , Office: +1 (323) 361-2688 Fax: +1 (323) 361-1510
| | - Hermien E. Kan
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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31
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Rasmussen JM, Entringer S, Nguyen A, van Erp TGM, Guijarro A, Oveisi F, Swanson JM, Piomelli D, Wadhwa PD, Buss C, Potkin SG. Brown adipose tissue quantification in human neonates using water-fat separated MRI. PLoS One 2013; 8:e77907. [PMID: 24205024 PMCID: PMC3813555 DOI: 10.1371/journal.pone.0077907] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/13/2013] [Indexed: 01/01/2023] Open
Abstract
There is a major resurgence of interest in brown adipose tissue (BAT) biology, particularly regarding its determinants and consequences in newborns and infants. Reliable methods for non-invasive BAT measurement in human infants have yet to be demonstrated. The current study first validates methods for quantitative BAT imaging of rodents post mortem followed by BAT excision and re-imaging of excised tissues. Identical methods are then employed in a cohort of in vivo infants to establish the reliability of these measures and provide normative statistics for BAT depot volume and fat fraction. Using multi-echo water-fat MRI, fat- and water-based images of rodents and neonates were acquired and ratios of fat to the combined signal from fat and water (fat signal fraction) were calculated. Neonatal scans (n = 22) were acquired during natural sleep to quantify BAT and WAT deposits for depot volume and fat fraction. Acquisition repeatability was assessed based on multiple scans from the same neonate. Intra- and inter-rater measures of reliability in regional BAT depot volume and fat fraction quantification were determined based on multiple segmentations by two raters. Rodent BAT was characterized as having significantly higher water content than WAT in both in situ as well as ex vivo imaging assessments. Human neonate deposits indicative of bilateral BAT in spinal, supraclavicular and axillary regions were observed. Pairwise, WAT fat fraction was significantly greater than BAT fat fraction throughout the sample (ΔWAT-BAT = 38 %, p<10(-4)). Repeated scans demonstrated a high voxelwise correlation for fat fraction (Rall = 0.99). BAT depot volume and fat fraction measurements showed high intra-rater (ICCBAT,VOL = 0.93, ICCBAT,FF = 0.93) and inter-rater reliability (ICCBAT,VOL = 0.86, ICCBAT,FF = 0.93). This study demonstrates the reliability of using multi-echo water-fat MRI in human neonates for quantification throughout the torso of BAT depot volume and fat fraction measurements.
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Affiliation(s)
- Jerod M. Rasmussen
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, California, United States of America
| | - Sonja Entringer
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Annie Nguyen
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Theo G. M. van Erp
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, California, United States of America
| | - Ana Guijarro
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, California, United States of America
| | - Fariba Oveisi
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, California, United States of America
| | - James M. Swanson
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Daniele Piomelli
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, California, United States of America
- Drug Discovery and Development, Instituto Italiano de Tecnologia Italian, Genoa, Italy
| | - Pathik D. Wadhwa
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, California, United States of America
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
- Department of Obstetrics & Gynecology, University of California Irvine, Irvine, California, United States of America
- Department of Epidemiology, University of California Irvine, Irvine, California, United States of America
| | - Claudia Buss
- Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
- Department of Medical Psychology, Charité, Berlin, Germany
- * E-mail: (CB); (SGP)
| | - Steven G. Potkin
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, California, United States of America
- * E-mail: (CB); (SGP)
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32
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Hyperpolarization without persistent radicals for in vivo real-time metabolic imaging. Proc Natl Acad Sci U S A 2013; 110:18064-9. [PMID: 24145405 DOI: 10.1073/pnas.1314928110] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hyperpolarized substrates prepared via dissolution dynamic nuclear polarization have been proposed as magnetic resonance imaging (MRI) agents for cancer or cardiac failure diagnosis and therapy monitoring through the detection of metabolic impairments in vivo. The use of potentially toxic persistent radicals to hyperpolarize substrates was hitherto required. We demonstrate that by shining UV light for an hour on a frozen pure endogenous substance, namely the glucose metabolic product pyruvic acid, it is possible to generate a concentration of photo-induced radicals that is large enough to highly enhance the (13)C polarization of the substance via dynamic nuclear polarization. These radicals recombine upon dissolution and a solution composed of purely endogenous products is obtained for performing in vivo metabolic hyperpolarized (13)C MRI with high spatial resolution. Our method opens the way to safe and straightforward preclinical and clinical applications of hyperpolarized MRI because the filtering procedure mandatory for clinical applications and the associated pharmacological tests necessary to prevent contamination are eliminated, concurrently allowing a decrease in the delay between preparation and injection of the imaging agents for improved in vivo sensitivity.
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