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Clemente-Suárez VJ, Martín-Rodríguez A, Redondo-Flórez L, López-Mora C, Yáñez-Sepúlveda R, Tornero-Aguilera JF. New Insights and Potential Therapeutic Interventions in Metabolic Diseases. Int J Mol Sci 2023; 24:10672. [PMID: 37445852 DOI: 10.3390/ijms241310672] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/13/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Endocrine homeostasis and metabolic diseases have been the subject of extensive research in recent years. The development of new techniques and insights has led to a deeper understanding of the mechanisms underlying these conditions and opened up new avenues for diagnosis and treatment. In this review, we discussed the rise of metabolic diseases, especially in Western countries, the genetical, psychological, and behavioral basis of metabolic diseases, the role of nutrition and physical activity in the development of metabolic diseases, the role of single-cell transcriptomics, gut microbiota, epigenetics, advanced imaging techniques, and cell-based therapies in metabolic diseases. Finally, practical applications derived from this information are made.
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Affiliation(s)
- Vicente Javier Clemente-Suárez
- Faculty of Sports Sciences, Universidad Europea de Madrid, Tajo Street, s/n, 28670 Madrid, Spain
- Grupo de Investigación en Cultura, Educación y Sociedad, Universidad de la Costa, Barranquilla 080002, Colombia
| | | | - Laura Redondo-Flórez
- Department of Health Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Tajo Street s/n, 28670 Villaviciosa de Odon, Spain
| | - Clara López-Mora
- Facultad de Ciencias Biomédicas y de la Salud, Universidad Europea de Valencia, Pg. de l'Albereda, 7, 46010 València, Spain
| | - Rodrigo Yáñez-Sepúlveda
- Faculty of Education and Social Sciences, Universidad Andres Bello, Viña del Mar 2520000, Chile
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Sex-dependent effects of forced exercise in the body composition of adolescent rats. Sci Rep 2021; 11:10154. [PMID: 33980961 PMCID: PMC8115159 DOI: 10.1038/s41598-021-89584-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/26/2021] [Indexed: 12/14/2022] Open
Abstract
Determining the body composition during adolescence can predict diseases such as obesity, diabetes, and metabolic syndromes later in life; and physical activity became an effective way to restore changes in body composition. However, current available literature assessing the body composition before, during and after adolescence in female and male rodents by in vivo techniques is scarce. Thus, by using computerized tomography, we aimed to define the baseline of the weight and body composition during the adolescence and young adulthood of female and male Sprague-Dawley rats (on P30, P60 and P90) under standard diet. Then, we determined the effect of 18 days of forced exercise on the body weight and composition during the early adolescence (P27-45). The highest percentual increments in weight, body volume and relative adipose contents occurred during the female and male adolescence. Forced running during the early adolescence decreased weight, body volume and relative adipose delta and increment values in males only. The adolescence of rats is a period of drastic body composition changes, where exercise interventions have sex-dependent effects. These results support a model that could open new research windows in the field of adolescent obesity.
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Dalili D, Isaac A, Bazzocchi A, Åström G, Bergh J, Lalam R, Weber MA, Fritz J, Mansour R. Interventional Techniques for Bone and Musculoskeletal Soft Tissue Tumors: Current Practices and Future Directions - Part I. Ablation. Semin Musculoskelet Radiol 2020; 24:692-709. [PMID: 33307585 DOI: 10.1055/s-0040-1719103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Musculoskeletal (MSK) image-guided oncologic intervention is an established field within radiology. Numerous studies have described its clinical benefits, safety, cost effectiveness, patient satisfaction, and improved quality of life, thereby establishing image-guided oncologic intervention as a preferred pathway in treating patients presenting with specific benign MSK tumors. But there is a paradigm shift on the horizon because these techniques may also support established pillars (surgery, systemic treatment, radiotherapy) in the treatment of malignant MSK tumors. Unlike benign tumors, where they are used as primary therapy lines with curative intent, such interventions can be selected for malignant tumors as adjuvant treatment in painful or unstable bone or soft tissue lesions or as more palliative therapy strategies. Using examples from our clinical practices, we elaborate on the benefits of applying a multidisciplinary approach (traditionally involving MSK radiologists, oncologists, orthopaedic surgeons, microbiologists, pathologists, physiotherapists, and pain management experts), ideally within a sarcoma treatment center to deliver a patient-specific therapy plan and illustrate methods to assess the benefits of this model of care.In this article, we review the current repertoire of ablation techniques, demonstrate why such procedures offer value-based alternatives to conventional treatments of specific tumors, and reflect on future directions. Additionally, we review the advantages and limitations of each technique and offer guidance to improve outcomes.
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Affiliation(s)
- Danoob Dalili
- Department of Radiology, Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom.,School of Biomedical Engineering and Imaging Sciences, Kings College London, London, United Kingdom
| | - Amanda Isaac
- School of Biomedical Engineering and Imaging Sciences, Kings College London, London, United Kingdom
| | - Alberto Bazzocchi
- Diagnostic and Interventional Radiology, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Gunnar Åström
- Department of Immunology, Genetics and Pathology (Oncology) and department of Surgical Sciences (Radiology), Uppsala University, Uppsala, Sweden
| | - Jonas Bergh
- Department of Oncology, Karolinska Institutet, Karolinska University Hospital Stockholm, Sweden
| | - Radhesh Lalam
- Department of Radiology, Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, United Kingdom
| | - Marc-André Weber
- Institute of Diagnostic and Interventional Radiology, Paediatric Radiology and Neuroradiology, University Medical Centre Rostock, Rostock, Germany
| | - Jan Fritz
- Department of Radiology, New York University Grossman School of Medicine, New York
| | - Ramy Mansour
- Department of Radiology, Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
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Hu Q, Cao H, Zhou L, Liu J, Di W, Lv S, Ding G, Tang L. Measurement of BAT activity by targeted molecular magnetic resonance imaging. Magn Reson Imaging 2020; 77:1-6. [PMID: 33309921 DOI: 10.1016/j.mri.2020.12.006] [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: 05/11/2020] [Revised: 10/29/2020] [Accepted: 12/08/2020] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The aim of this study was to measure brown adipose tissue (BAT) activity by targeted peptide (CKGGRAKDC-NH2)-coupled, polyethylene glycol (PEG)-coated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles with magnetic resonance imaging (MRI). METHODS The peptide was conjugated with PEG-coated USPIO to obtain targeted probes. Male C57BL/6 J mice were randomly divided into cold exposing and control group (n = 5 per group). T2*-weighted images were obtained pre- and post-contrast probes. Histological and gene expression analyses were carried out. RESULTS T2* relaxation time of BAT in the cold exposing group decreased more significantly compared to the control group. The calculated R2* increased with the reduction of T2* value. The ΔR2* (26.68 s-1) of BAT in the cold exposing group was significantly higher (P < 0.05) than the control group. Iron particle sediments in BAT of the cold exposing group were revealed more than the control group with Prussian blue staining. The UCP1 expression level was up-regulated after cold activation. CONCLUSIONS BAT activity could be measured in vivo by the targeted peptide-coupled, PEG-coated USPIOs with MRI.
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Affiliation(s)
- Qingqiao Hu
- Departments of Nuclear Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, People's Republic of China
| | - Huixiao Cao
- Departments of Nuclear Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, People's Republic of China
| | - Lu Zhou
- Departments of Nuclear Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, People's Republic of China
| | - Juan Liu
- Department of Geratology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, People's Republic of China
| | - Wenjuan Di
- Department of Geratology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, People's Republic of China
| | - Shan Lv
- Department of Geratology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, People's Republic of China
| | - Guoxian Ding
- Department of Geratology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, People's Republic of China.
| | - Lijun Tang
- Departments of Nuclear Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, People's Republic of China.
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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: 12] [Impact Index Per Article: 3.0] [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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Henningsson M, Brundin M, Scheffel T, Edin C, Viola F, Carlhäll CJ. Quantification of epicardial fat using 3D cine Dixon MRI. BMC Med Imaging 2020; 20:80. [PMID: 32664848 PMCID: PMC7362508 DOI: 10.1186/s12880-020-00478-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/02/2020] [Indexed: 11/10/2022] Open
Abstract
Background There is an increased interest in quantifying and characterizing epicardial fat which has been linked to various cardiovascular diseases such as coronary artery disease and atrial fibrillation. Recently, three-dimensional single-phase Dixon techniques have been used to depict the heart and to quantify the surrounding fat. The purpose of this study was to investigate the merits of a new high-resolution cine 3D Dixon technique for quantification of epicardial adipose tissue and compare it to single-phase 3D Dixon in patients with cardiovascular disease. Methods Fifteen patients referred for clinical CMR examination of known or suspected heart disease were scanned on a 1.5 T scanner using single-phase Dixon and cine Dixon. Epicardial fat was segmented by three readers and intra- and inter-observer variability was calculated per slice. Cine Dixon segmentation was performed in the same cardiac phase as single-phase Dixon. Subjective image quality assessment of water and fat images were performed by three readers using a 4-point Likert scale (1 = severe; 2 = significant; 3 = mild; 4 = no blurring of cardiac structures). Results Intra-observer variability was excellent for cine Dixon images (ICC = 0.96), and higher than single-phase Dixon (ICC = 0.92). Inter-observer variability was good for cine Dixon (ICC = 0.76) and moderate for single-phase Dixon (ICC = 0.63). The intra-observer measurement error (mean ± standard deviation) per slice for cine was − 0.02 ± 0.51 ml (− 0.08 ± 0.4%), and for single-phase 0.39 ± 0.72 ml (0.18 ± 0.41%). Inter-observer measurement error for cine was 0.46 ± 0.98 ml (0.11 ± 0.46%) and for single-phase 0.42 ± 1.53 ml (0.17 ± 0.47%). Visual scoring of the water image yielded median of 2 (interquartile range = [Q3-Q1] 2–2) for cine and median of 3 (interquartile range = 3–2) for single-phase (P < 0.05) while no significant difference was found for the fat images, both techniques yielding a median of 3 and interquartile range of 3–2. Conclusion Cine Dixon can be used to quantify epicardial fat with lower intra- and inter-observer variability compared to standard single-phase Dixon. The time-resolved information provided by the cine acquisition appears to support the delineation of the epicardial adipose tissue depot.
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Affiliation(s)
- Markus Henningsson
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden. .,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden. .,School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
| | - Martin Brundin
- Department of Clinical Physiology, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Tobias Scheffel
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Carl Edin
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Federica Viola
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Carl-Johan Carlhäll
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Department of Clinical Physiology, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
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Junker D, Syväri J, Weidlich D, Holzapfel C, Drabsch T, Waschulzik B, Rummeny EJ, Hauner H, Karampinos DC. Investigation of the Relationship between MR-Based Supraclavicular Fat Fraction and Thyroid Hormones. Obes Facts 2020; 13:331-343. [PMID: 32564012 PMCID: PMC7445585 DOI: 10.1159/000507294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 03/13/2020] [Indexed: 01/12/2023] Open
Abstract
PURPOSE Brown adipose tissue (BAT) plays a potential role in energy and glucose metabolism in humans. Thyroid hormones (TH) are main regulators of BAT development and function. However, it remains unknown how the magnetic resonance (MR)-based proton density fat fraction (PDFF) of supraclavicular adipose tissue used as a surrogate marker for BAT presence relates to TH. Therefore, the purpose of this analysis was to investigate the relationship between supraclavicular PDFF and serum levels of TH. METHODS In total, 96 adult volunteers from a large cross-sectional study who underwent additional MR examination of the neck and pelvis were included in this analysis. Segmented PDFF maps of the supraclavicular and gluteal subcutaneous adipose tissue were generated. Delta PDFF was calculated as the difference between gluteal and supraclavicular PDFF and grouped as high (≥12%) or low (<12%) based on the median and the clinical rationale of a high versus low probability of BAT being present. Thyroid-stimulating hormone (mIU/L), free triiodothyronine (FT3, pg/mL) and free thyroxine (FT4, ng/dL) levels were determined in blood samples. Body mass index (BMI) was calculated as weight (kg)/height (m)2. Statistical analyses included the use of paired samples ttest, simple linear regression analysis and a multivariable linear regression analysis. RESULTS The median age of the subjects (77% female) was 33 years, BMI ranged from 17.2 to 43.1 kg/m2. Supraclavicular and gluteal PDFF differed significantly (76.5 ± 4.8 vs. 89.4 ± 3.5 %, p < 0.01). Supraclavicular PDFF was associated with FT3 in subjects with high delta PDFF (R2 = 0.17, p < 0.01), with higher FT3 being associated with lower supraclavicular PDFF (y = 85.2 + -3.6 x). In a multivariable linear regression analysis considering further potential prognostic factors, the interaction between the delta PDFF group and FT3 remained a predictor for supraclavicular PDFF (B = -4.65, p < 0.01). DISCUSSION/CONCLUSIONS Supraclavicular PDFF corresponds to the presence of BAT. In the present analysis, supraclavicular PDFF is correlated with FT3 in subjects with high delta PDFF. Therefore, the present findings suggest that biologically active T3 may be involved in the development of supraclavicular BAT.
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Affiliation(s)
- Daniela Junker
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany,
| | - Jan Syväri
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Dominik Weidlich
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Christina Holzapfel
- Institute for Nutritional Medicine, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Theresa Drabsch
- Institute for Nutritional Medicine, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Birgit Waschulzik
- Institute of Medical Informatics, Statistics and Epidemiology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Ernst J Rummeny
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Hans Hauner
- Institute for Nutritional Medicine, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
- Else Kroener-Fresenius-Center of Nutritional Medicine, ZIEL Institute for Food and Health, Technical University of Munich, Freising, Germany
| | - Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
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Li L, Scotti A, Fang J, Yin L, Xiong T, He W, Qin Y, Liew C, Khayyat N, Zhu W, Cai K. Characterization of brown adipose tissue (BAT) in polycystic ovary syndrome (PCOS) patients by Z-Spectral Imaging (ZSI). Eur J Radiol 2019; 123:108777. [PMID: 31855655 DOI: 10.1016/j.ejrad.2019.108777] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 11/06/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE To characterize brown adipose tissue (BAT) in polycystic ovary syndrome (PCOS) patients in comparison to healthy subjects using Z-spectral imaging (ZSI). METHOD ZSI data were collected on 19 normal control females (NCF), 17 males (NCM), and 13 PCOS patients. By fitting to multiple Lorentzian functions, ZSI provides fat-water fraction (FWF) of tissue in the supraclavicular area that can be used to differentiate between white adipose tissue (WAT), BAT, and muscle. The fraction of BAT over the total fat depot (BATf) and the average FWF in BAT or FWF(BAT) were then computed, reflecting relative BAT mass and BAT metabolism respectively. The parameters were compared among the three groups, and the correlations to Body Mass Index (BMI) were also quantified. RESULTS There was an inverse correlation between BATf and BMI in normal subjects. The BATf of the PCOS group was significantly smaller than the NCF (P < 0.001). On the other hand, FWF(BAT) correlated linearly with BMI in healthy subjects. The PCOS group had higher FWF(BAT) than the NCF group (P < 0.001). CONCLUSIONS Normal subjects with higher BMI show less BATf and have increased FWF(BAT), indicating relatively higher level of metabolic passive WAT depot and relatively reduced metabolism in their BAT depots. PCOS patients have the least BATf and the highest FWF(BAT), suggesting decreased BAT mass and function in PCOS. Novel imaging technique with ZSI for the characterization of BAT mass and function in PCOS may help to monitor treatment responses of PCOS therapies.
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Affiliation(s)
- Li Li
- Radiology Department, Tongji Hospital, Tongji Medical College, HUST, Wuhan, Hubei, PR China; Radiology Dept., College of Medicine, University of Illinois at Chicago, IL, USA
| | - Alessandro Scotti
- Radiology Dept., College of Medicine, University of Illinois at Chicago, IL, USA; Bioengineering Dept., College of Medicine, University of Illinois at Chicago, IL, USA
| | - Jicheng Fang
- Radiology Department, Tongji Hospital, Tongji Medical College, HUST, Wuhan, Hubei, PR China
| | - Li Yin
- Gynaecology and Obstetrics Dept., Tongji Hospital, Tongji Medical College, HUST, Wuhan, Hubei, PR China
| | - Ting Xiong
- Gynaecology and Obstetrics Dept., Tongji Hospital, Tongji Medical College, HUST, Wuhan, Hubei, PR China
| | - WenTao He
- Endocrinology Dept., Tongji Hospital, Tongji Medical College, HUST, Wuhan, Hubei, PR China
| | - Yuanyuan Qin
- Radiology Department, Tongji Hospital, Tongji Medical College, HUST, Wuhan, Hubei, PR China
| | - ChongWee Liew
- Physiology & Biophysics Dept., College of Medicine, University of Illinois at Chicago, IL, USA
| | - Nael Khayyat
- Radiology Dept., College of Medicine, University of Illinois at Chicago, IL, USA
| | - WenZhen Zhu
- Radiology Department, Tongji Hospital, Tongji Medical College, HUST, Wuhan, Hubei, PR China.
| | - Kejia Cai
- Radiology Dept., College of Medicine, University of Illinois at Chicago, IL, USA; Bioengineering Dept., College of Medicine, University of Illinois at Chicago, IL, USA.
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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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10
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Gashi G, Madoerin P, Maushart CI, Michel R, Senn JR, Bieri O, Betz MJ. MRI characteristics of supraclavicular brown adipose tissue in relation to cold-induced thermogenesis in healthy human adults. J Magn Reson Imaging 2019; 50:1160-1168. [PMID: 30945366 DOI: 10.1002/jmri.26733] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 03/13/2019] [Accepted: 03/14/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Brown adipose tissue (BAT) has been proposed as a target to treat obesity and metabolic disease. Currently, 18 F-Fluordeoxyglucose positron emission tomography (FDG-PET) is the standard for BAT-imaging. MRI might be a promising alternative, as it is not associated with ionizing radiation, offers a high resolution, and allows to discriminate different types of soft tissue. PURPOSE We sought to evaluate whether supraclavicular BAT (scBAT) volume, fat-fraction (FF), and relaxation rate (R2*) determined by MRI can predict its metabolic activity, which was assessed by measurement of cold-induced thermogenesis (CIT). STUDY TYPE Prospective cohort study. SUBJECTS Twenty healthy volunteers (9 female, 11 male), aged 18-47 years, with a body mass index (BMI) of 18-30 kg/m2 . FIELD STRENGTH/SEQUENCE Multiecho gradient MRI for water-fat separation was used on a 3T device to measure the FF and T2 * of BAT. ASSESSMENT Prior to imaging, CIT was determined by measuring the difference in energy expenditure (EE) during warm conditions and after cold exposure. Volume, FF, and R2* of scBAT was assessed and compared with CIT. In 11 participants, two MRI sessions with and without cold exposure were performed and the dynamic changes in FF and R2* assessed. STATISTICAL TESTS Linear regression was used to evaluate the relation of MRI measurements and CIT. P-values below 0.05 were considered significant; data are given as mean ± SD. RESULTS R2* correlated positively with CIT (r = 0.64, R2 = 0.41 P = 0.0041). Volume and FF did not correlate significantly with CIT. After mild cold exposure EE increased significantly (P = 0.0002), with a mean CIT of 147 kcal/day. The mean volume of scBAT was 72.4 ± 38.4 ml, mean FF was 74.3 ± 5.8%, and the mean R2* (1/T2 *) was 33.5 ± 12.7 s-1 . DATA CONCLUSION R2* of human scBAT can be used to estimate CIT. FF of scBAT was not associated with CIT. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1160-1168.
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Affiliation(s)
- Gani Gashi
- Department of Endocrinology, Diabetes and Metabolism, University Hospital of Basel and University of Basel, Basel, Switzerland
| | - Philipp Madoerin
- Department of Radiology, University Hospital of Basel and University of Basel, Basel, Switzerland
| | - Claudia I Maushart
- Department of Endocrinology, Diabetes and Metabolism, University Hospital of Basel and University of Basel, Basel, Switzerland
| | - Regina Michel
- Department of Endocrinology, Diabetes and Metabolism, University Hospital of Basel and University of Basel, Basel, Switzerland
| | - Jaël-Rut Senn
- Department of Endocrinology, Diabetes and Metabolism, University Hospital of Basel and University of Basel, Basel, Switzerland
| | - Oliver Bieri
- Department of Radiology, University Hospital of Basel and University of Basel, Basel, Switzerland
| | - Matthias J Betz
- Department of Endocrinology, Diabetes and Metabolism, University Hospital of Basel and University of Basel, Basel, Switzerland
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11
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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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Borga M. MRI adipose tissue and muscle composition analysis-a review of automation techniques. Br J Radiol 2018; 91:20180252. [PMID: 30004791 PMCID: PMC6223175 DOI: 10.1259/bjr.20180252] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 06/12/2018] [Accepted: 07/09/2018] [Indexed: 02/06/2023] Open
Abstract
MRI is becoming more frequently used in studies involving measurements of adipose tissue and volume and composition of skeletal muscles. The large amount of data generated by MRI calls for automated analysis methods. This review article presents a summary of automated and semi-automated techniques published between 2013 and 2017. Technical aspects and clinical applications for MRI-based adipose tissue and muscle composition analysis are discussed based on recently published studies. The conclusion is that very few clinical studies have used highly automated analysis methods, despite the rapidly increasing use of MRI for body composition analysis. Possible reasons for this are that the availability of highly automated methods has been limited for non-imaging experts, and also that there is a limited number of studies investigating the reproducibility of automated methods for MRI-based body composition analysis.
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Affiliation(s)
- Magnus Borga
- Department
of Biomedical Engineering and Center for Medical Image Science and
Visualization (CMIV), Linköping University,
Linköping, Sweden
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13
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Emont MP, Kim DI, Wu J. Development, activation, and therapeutic potential of thermogenic adipocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:13-19. [PMID: 29763732 DOI: 10.1016/j.bbalip.2018.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 02/23/2018] [Accepted: 05/10/2018] [Indexed: 01/28/2023]
Abstract
During the last decade, significant progress has been made in understanding adipocytes with a particular focus on thermogenic fat cells, which effectively convert chemical energy into heat in addition to their other metabolic functions. It has been increasingly recognized that different types and subtypes of adipocytes exist and the developmental origins of various types of fat cells are being intensively investigated. Previous work using immortalized fat cell lines has established an intricate transcriptional network that regulates adipocyte function. Recent work has illustrated how these key transcriptional components mediate thermogenic activation in fat cells. Last but not least, cumulative evidence supports an incontestable role of thermogenic fat in influencing systemic metabolism in humans. Here we summarize the exciting advancements in our understanding of thermogenic fat, discuss the advantages and limitations of the experimental tools currently available, and explore the future directions of this fast-evolving field.
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Affiliation(s)
- Margo P Emont
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dong-Il Kim
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jun Wu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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14
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Morales Drissi N, Romu T, Landtblom AM, Szakács A, Hallböök T, Darin N, Borga M, Leinhard OD, Engström M. Unexpected Fat Distribution in Adolescents With Narcolepsy. Front Endocrinol (Lausanne) 2018; 9:728. [PMID: 30574118 PMCID: PMC6292486 DOI: 10.3389/fendo.2018.00728] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 11/16/2018] [Indexed: 02/02/2023] Open
Abstract
Narcolepsy type 1 is a chronic sleep disorder with significantly higher BMI reported in more than 50% of adolescent patients, putting them at a higher risk for metabolic syndrome in adulthood. Although well-documented, the body fat distribution and mechanisms behind weight gain in narcolepsy are still not fully understood but may be related to the loss of orexin associated with the disease. Orexin has been linked to the regulation of brown adipose tissue (BAT), a metabolically active fat involved in energy homeostasis. Previous studies have used BMI and waist circumference to characterize adipose tissue increases in narcolepsy but none have investigated its specific distribution. Here, we examine adipose tissue distribution in 19 adolescent patients with narcolepsy type 1 and compare them to 17 of their healthy peers using full body magnetic resonance imaging (MRI). In line with previous findings we saw that the narcolepsy patients had more overall fat than the healthy controls, but contrary to our expectations there were no group differences in supraclavicular BAT, suggesting that orexin may have no effect at all on BAT, at least under thermoneutral conditions. Also, in line with previous reports, we observed that patients had more total abdominal adipose tissue (TAAT), however, we found that they had a lower ratio between visceral adipose tissue (VAT) and TAAT indicating a relative increase of subcutaneous abdominal adipose tissue (ASAT). This relationship between VAT and ASAT has been associated with a lower risk for metabolic disease. We conclude that while weight gain in adolescents with narcolepsy matches that of central obesity, the lower VAT ratio may suggest a lower risk of developing metabolic disease.
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Affiliation(s)
- Natasha Morales Drissi
- Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
| | - Thobias Romu
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- AMRA Medical AB, Linköping, Sweden
| | - Anne-Marie Landtblom
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine (IKE), Linköping University, Linköping, Sweden
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Attilla Szakács
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Tove Hallböök
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Darin
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Magnus Borga
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- AMRA Medical AB, Linköping, Sweden
- Department of Biomedical Engineering (IMT), Linköping University, Linköping, Sweden
| | - Olof Dahlqvist Leinhard
- Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- AMRA Medical AB, Linköping, Sweden
| | - Maria Engström
- Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- *Correspondence: Maria Engström
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15
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Association between supraclavicular brown adipose tissue composition at birth and adiposity gain from birth to 6 months of age. Pediatr Res 2017; 82:1017-1021. [PMID: 28723888 PMCID: PMC5685919 DOI: 10.1038/pr.2017.159] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 06/26/2017] [Indexed: 12/11/2022]
Abstract
BackgroundBrown adipose tissue (BAT) is associated with higher energy expenditure and lower adiposity in adults. However, the relationship between BAT composition and adiposity in early life is unknown. The objective of this study was to test the hypothesis that brown fat composition at birth is prospectively associated with adiposity gain during the first 6 months of postnatal life.MethodsN=35 healthy infants were followed up prospectively from intrauterine life and birth through 6 months of age. Dixon magnetic resonance imaging (MRI) scans were conducted during the neonatal period to characterize supraclavicular BAT composition. Dual-energy X-ray absorptiometry to assess total body composition was performed within the first and sixth months of life.ResultsAfter adjusting for potential confounding factors, a more brown-like composition (smaller fat fraction) of the supraclavicular BAT depot was associated with a smaller increase in percent body fat over the first 6 months of postnatal life.ConclusionsA more brown-like BAT composition at birth appears to be protective against excess adiposity gain in early life. Newborn BAT tissue may constitute a target for prevention strategies against the subsequent development of obesity.
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16
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Loh RKC, Kingwell BA, Carey AL. Human brown adipose tissue as a target for obesity management; beyond cold-induced thermogenesis. Obes Rev 2017; 18:1227-1242. [PMID: 28707455 DOI: 10.1111/obr.12584] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/01/2017] [Accepted: 06/01/2017] [Indexed: 02/01/2023]
Abstract
Elevating energy expenditure via adaptive thermogenesis in brown adipose tissue (BAT) is a potential strategy to reverse obesity. Much early enthusiasm for this approach, based on rodent studies, was tempered by the belief that BAT was relatively inconsequential in healthy adult humans. Interest was reinvigorated a decade ago when a series of studies re-identified BAT, primarily in upper thoracic regions, in adults. Despite the ensuing explosion of pre-clinical investigations and identification of an extensive list of potential target molecules for BAT recruitment, our understanding of human BAT physiology remains limited, particularly regarding interventions which might hold therapeutic promise. Cold-induced BAT thermogenesis (CIT) has been well studied, although is not readily translatable as an anti-obesity approach, whereas little is known regarding the role of BAT in human diet-induced thermogenesis (DIT). Furthermore, human studies dedicated to translating known pharmacological mechanisms of adipose browning from animal models are sparse. Several lines of recent evidence suggest that molecular regulation and physiology of human BAT differ to that of laboratory rodents, which form the majority of our knowledge base. This review will summarize knowledge on CIT and expand upon the current understanding and evidence gaps related to human adaptive thermogenesis via mechanisms other than cold.
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Affiliation(s)
- R K C Loh
- Metabolic and Vascular Physiology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - B A Kingwell
- Metabolic and Vascular Physiology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - A L Carey
- Metabolic and Vascular Physiology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
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17
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MacCannell A, Sinclair K, Friesen-Waldner L, McKenzie CA, Staples JF. Water-fat MRI in a hibernator reveals seasonal growth of white and brown adipose tissue without cold exposure. J Comp Physiol B 2017; 187:759-767. [PMID: 28324157 DOI: 10.1007/s00360-017-1075-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 12/13/2016] [Accepted: 02/26/2017] [Indexed: 11/24/2022]
Abstract
Obligate hibernators, such as ground squirrels, display circannual patterns which persist even under constant laboratory conditions, suggesting that they are regulated by endogenous rhythms. Brown adipose tissue (BAT) is important for thermogenesis during periodic arousals from hibernation when core body temperature rises spontaneously from 5 to 37 °C. In most small eutherians BAT growth requires several weeks of cold exposure. We hypothesized that in the thirteen-lined ground squirrel (Ictidomys tridecemlineatus), a hibernator, BAT growth is regulated, in part, by an endogenous rhythm and we predicted that this growth would precede the hibernation season without cold exposure. We tested this prediction using repeated water-fat magnetic resonance imaging over a year, including the hibernation season. Thoracic BAT depots increased in volume from spring through autumn even though animals were housed at ~22 °C. Subsequent cold exposure (5 °C) enlarged the thoracic BAT further. The fat fraction of this tissue fell significantly during the period of peak growth, indicating relative increases in non-triglyceride components, perhaps mitochondria or vasculature. We also found that the proportion of the body consisting of white adipose tissue (WAT) increased steadily from spring through autumn, and fell throughout hibernation, mirroring changes in body mass. Unlike BAT, WAT fat fractions remained constant (near 90%) throughout the year. Future studies will evaluate the significance of photoperiod and cold exposure on the growth of these tissues. We also found tissue with a fat fraction characteristic of BAT in the head near the eyes, a potentially novel discovery that requires further confirmation.
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Affiliation(s)
- Amanda MacCannell
- Department of Biology, University of Western Ontario, London, ON, N6A 5B8, Canada
| | - Kevin Sinclair
- Medical Biophysics, University of Western Ontario, London, ON, N6A 5B8, Canada
| | | | - Charles A McKenzie
- Medical Biophysics, University of Western Ontario, London, ON, N6A 5B8, Canada
| | - James F Staples
- Department of Biology, University of Western Ontario, London, ON, N6A 5B8, Canada.
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18
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Romu T, Dahlström N, Leinhard OD, Borga M. Robust water fat separated dual-echo MRI by phase-sensitive reconstruction. Magn Reson Med 2016; 78:1208-1216. [DOI: 10.1002/mrm.26488] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/22/2016] [Accepted: 09/11/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Thobias Romu
- Department of Biomedical Engineering; Linköping University; Linköping Sweden
- Center for Medical Image Science and Visualization (CMIV); Linköping University; Linköping Sweden
| | - Nils Dahlström
- Center for Medical Image Science and Visualization (CMIV); Linköping University; Linköping Sweden
- Department of Radiology, Department of Medical and Health Sciences; Linköping University; Linköping Sweden
| | - Olof Dahlqvist Leinhard
- Center for Medical Image Science and Visualization (CMIV); Linköping University; Linköping Sweden
- Department of Medical and Health Sciences; Linköping University; Linköping Sweden
| | - Magnus Borga
- Department of Biomedical Engineering; Linköping University; Linköping Sweden
- Center for Medical Image Science and Visualization (CMIV); Linköping University; Linköping Sweden
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19
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Romu T, Vavruch C, Dahlqvist-Leinhard O, Tallberg J, Dahlström N, Persson A, Heglind M, Lidell ME, Enerbäck S, Borga M, Nystrom FH. A randomized trial of cold-exposure on energy expenditure and supraclavicular brown adipose tissue volume in humans. Metabolism 2016; 65:926-34. [PMID: 27173471 DOI: 10.1016/j.metabol.2016.03.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 03/10/2016] [Accepted: 03/25/2016] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To study if repeated cold-exposure increases metabolic rate and/or brown adipose tissue (BAT) volume in humans when compared with avoiding to freeze. DESIGN Randomized, open, parallel-group trial. METHODS Healthy non-selected participants were randomized to achieve cold-exposure 1hour/day, or to avoid any sense of feeling cold, for 6weeks. Metabolic rate (MR) was measured by indirect calorimetry before and after acute cold-exposure with cold vests and ingestion of cold water. The BAT volumes in the supraclavicular region were measured with magnetic resonance imaging (MRI). RESULTS Twenty-eight participants were recruited, 12 were allocated to controls and 16 to cold-exposure. Two participants in the cold group dropped out and one was excluded. Both the non-stimulated and the cold-stimulated MR were lowered within the group randomized to avoid cold (MR at room temperature from 1841±199 kCal/24h to 1795±213 kCal/24h, p=0.047 cold-activated MR from 1900±150 kCal/24h to 1793±215 kCal/24h, p=0.028). There was a trend towards increased MR at room temperature following the intervention in the cold-group (p=0.052). The difference between MR changes by the interventions between groups was statistically significant (p=0.008 at room temperature, p=0.032 after cold-activation). In an on-treatment analysis after exclusion of two participants that reported ≥8days without cold-exposure, supraclavicular BAT volume had increased in the cold-exposure group (from 0.0175±0.015l to 0.0216±0.014l, p=0.049). CONCLUSIONS We found evidence for plasticity in metabolic rate by avoiding to freeze compared with cold-exposure in a randomized setting in non-selected humans.
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Affiliation(s)
- Thobias Romu
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden; Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Camilla Vavruch
- Department of Medical and Health Sciences, Faculty of Medicine and Health Sciences, Linköping University
| | | | - Joakim Tallberg
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Nils Dahlström
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Anders Persson
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Mikael Heglind
- Department of Medical and Clinical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Martin E Lidell
- Department of Medical and Clinical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Sven Enerbäck
- Department of Medical and Clinical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Magnus Borga
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden; Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Fredrik H Nystrom
- Department of Medical and Health Sciences, Faculty of Medicine and Health Sciences, Linköping University.
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20
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Rodrigues DB, Stauffer PR, Colebeck E, Hood AZ, Salahi S, Maccarini PF, Topsakal E. Dielectric properties measurements of brown and white adipose tissue in rats from 0.5 to 10 GHz. Biomed Phys Eng Express 2016; 2:025005. [PMID: 29354288 PMCID: PMC5773071 DOI: 10.1088/2057-1976/2/2/025005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Brown adipose tissue (BAT) plays an important role in whole body metabolism and with appropriate stimulus could potentially mediate weight gain and insulin sensitivity. Although imaging techniques are available to detect subsurface BAT, there are currently no viable methods for continuous acquisition of BAT energy expenditure. Microwave (MW) radiometry is an emerging technology that allows the quantification of tissue temperature variations at depths of several centimeters. Such temperature differentials may be correlated with variations in metabolic rate, thus providing a quantitative approach to monitor BAT metabolism. In order to optimize MW radiometry, numerical and experimental phantoms with accurate dielectric properties are required to develop and calibrate radiometric sensors. Thus, we present for the first time, the characterization of relative permittivity and electrical conductivity of brown (BAT) and white (WAT) adipose tissues in rats across the MW range 0.5-10GHz. Measurements were carried out in situ and post mortem in six female rats of approximately 200g. A Cole-Cole model was used to fit the experimental data into a parametric model that describes the variation of dielectric properties as a function of frequency. Measurements confirm that the dielectric properties of BAT (εr = 14.0-19.4, σ = 0.3-3.3S/m) are significantly higher than those of WAT (εr = 9.1-11.9, σ = 0.1-1.9S/m), in accordance with the higher water content of BAT.
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Affiliation(s)
- D B Rodrigues
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - P R Stauffer
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - E Colebeck
- Department of Electrical and Computer Engineering, Mississippi State University, Starkville, MS 39762, USA
| | - A Z Hood
- Department of Electrical and Computer Engineering, Mississippi State University, Starkville, MS 39762, USA
| | | | - P F Maccarini
- Department of Biomedical Engineering, Duke University, Durham, NC 27710, USA
| | - E Topsakal
- Department of Electrical and Computer Engineering, Mississippi State University, Starkville, MS 39762, USA
- Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
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