1
|
Zhu C, Guo Y, Si W, Zhong Q, Mei Y, Feng Y, Zhang X. Detection of brown adipose tissue in rats with acute cold stimulation using quantitative susceptibility mapping. Chin Med J (Engl) 2023; 136:2137-2139. [PMID: 36374124 PMCID: PMC10476742 DOI: 10.1097/cm9.0000000000002388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Indexed: 11/16/2022] Open
Affiliation(s)
- Cuiling Zhu
- Department of Radiology, The Third Affiliated Hospital of Southern Medical University (Academy of Orthopedics Guangdong Province), Guangzhou, Guangdong 510630, China
- Department of Radiology, Foshan Hospital of Traditional Chinese Medicine, Foshan, Guangdong 528000, China
| | - Yihao Guo
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong 510515, China
- Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong 510515, China
- Guangdong Province Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Wenbin Si
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Qiaoling Zhong
- Department of Radiology, The Third Affiliated Hospital of Southern Medical University (Academy of Orthopedics Guangdong Province), Guangzhou, Guangdong 510630, China
| | - Yingjie Mei
- Philips Healthcare, Guangzhou, Guangdong 510000, China
| | - Yanqiu Feng
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong 510515, China
- Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong 510515, China
- Guangdong Province Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Xiaodong Zhang
- Department of Radiology, The Third Affiliated Hospital of Southern Medical University (Academy of Orthopedics Guangdong Province), Guangzhou, Guangdong 510630, China
| |
Collapse
|
2
|
Randomization, design and analysis for interdependency in aging research: no person or mouse is an island. NATURE AGING 2022; 2:1101-1111. [PMID: 37063472 PMCID: PMC10099485 DOI: 10.1038/s43587-022-00333-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Investigators traditionally use randomized designs and corresponding analysis procedures to make causal inferences about the effects of interventions, assuming independence between an individual's outcome and treatment assignment and the outcomes of other individuals in the study. Often, such independence may not hold. We provide examples of interdependency in model organism studies and human trials and group effects in aging research and then discuss methodologic issues and solutions. We group methodologic issues as they pertain to (1) single-stage individually randomized trials; (2) cluster-randomized controlled trials; (3) pseudo-cluster-randomized trials; (4) individually randomized group treatment; and (5) two-stage randomized designs. Although we present possible strategies for design and analysis to improve the rigor, accuracy and reproducibility of the science, we also acknowledge real-world constraints. Consequences of nonadherence, differential attrition or missing data, unintended exposure to multiple treatments and other practical realities can be reduced with careful planning, proper study designs and best practices.
Collapse
|
3
|
Frank L, Brandt S, Wabitsch M. Subcutaneous fat necrosis in newborns: a systematic literature review of case reports and model of pathophysiology. Mol Cell Pediatr 2022; 9:18. [PMID: 36427118 PMCID: PMC9700527 DOI: 10.1186/s40348-022-00151-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/09/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Subcutaneous fat necrosis of the newborn (SCFN) is a rare disease occurring in the first days of life. Characteristically, the infants show hard nodules in subcutaneous tissue, purple or erythematous in color and appear on the upper back, cheeks, buttocks and limbs. In most cases, SCFN is a self-limiting disease, as the nodules disappear in up to 6 months. A severe complication associated with SCFN is hypercalcaemia. Pathophysiological mechanisms causing SCFN or associated hypercalcaemia are not fully understood yet. METHODS A systematic literature research including the six biggest databases for medical research has been used to identify all published case reports of SCFN. N = 206 publications has been identified containing n = 320 case reports. All cases have been classified into four subgroups (depending on reported serum-calcium-level): hypercalcaemia, normocalcaemia, hypocalcaemia or no information given. Reported maternal factors, birth characteristics, details about SCFN, diagnostics, therapy and long-term observations have been extracted from publications. RESULTS This is the first systematic literature research that summed up all published cases of SCFN from 1948 up to 2018. Information about serum calcium level was given in 64.3% of the cases. From those, the majority showed hypercalcaemia (70.5%) (normocalcaemia 25.1%, hypocalcemia 4.3%). 89.3% of newborns with hypercalcaemia showed suppressed levels of the parathormone. Maternal gestational diabetes, maternal hypertensive diseases during pregnancy, macrosomia (> 4000g), asphyxia and therapeutic hypothermia are risk factors for SCFN. Histological findings showed a granulomatous inflammation in 98% of cases. CONCLUSION We identified that maternal, birth characteristics and therapeutic measures are probably risk factors for SCFN. These risk factors should be taken into account within the care of neonates.
Collapse
Affiliation(s)
- Leonie Frank
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
- Department of Orthopaedics and Trauma Surgery, Oberschwaben Clinic Wangen im Allgäu, Wangen im Allgäu, Germany
| | - Stephanie Brandt
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Martin Wabitsch
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany.
| |
Collapse
|
4
|
University of Alabama at Birmingham Nathan Shock Center: comparative energetics of aging. GeroScience 2021; 43:2149-2160. [PMID: 34304389 DOI: 10.1007/s11357-021-00414-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 12/09/2022] Open
Abstract
The UAB Nathan Shock Center focuses on comparative energetics and aging. Energetics, as defined for this purpose, encompasses the causes, mechanisms, and consequences of the acquisition, storage, and use of metabolizable energy. Comparative energetics is the study of metabolic processes at multiple scales and across multiple species as it relates to health and aging. The link between energetics and aging is increasingly understood in terms of dysregulated mitochondrial function, altered metabolic signaling, and aberrant nutrient responsiveness with increasing age. The center offers world-class expertise in comprehensive, integrated energetic assessment and analysis from the level of the organelle to the organism and across species from the size of worms to rats as well as state-of-the-art data analytics. The range of services offered by our three research cores, (1) The Organismal Energetics Core, (2) Mitometabolism Core, and (3) Data Analytics Core, is described herein.
Collapse
|
5
|
Zheng J, Gao J, Zhang Q, Wu X, Shen W, Sun M. Sirtuin 3 deficiency accelerates Angiotensin II-induced skeletal muscle atrophy. Connect Tissue Res 2020; 61:586-593. [PMID: 31340681 DOI: 10.1080/03008207.2019.1648443] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Background: It has been reported that Angiotensin II (Ang II) induced skeletal muscle atrophy. However, the precise mechanisms remain elusive. Sirtuin 3 (SIRT3), an NAD-dependent deacetylase, plays a central role in maintaining cellular metabolic homeostasis. This work aims to determine the role of SIRT3-mediated cellular metabolism in skeletal muscle wasting. Methods and Results: Eight-week-old male wild-type (WT) and SIRT3 knockout (SIRT3 KO) mice were infused with Ang II or saline for 4 weeks. Ang II induces skeletal muscle atrophy by inducing expression of the muscle-enriched E3 ubiquitin ligase muscle RING-finger-1 (MuRF1) and atrogin-1, accompanied by a reduction in SIRT3 in skeletal muscle. SIRT3 deficiency accelerated Ang II-induced loss of lean mass and protein hyper-acetylation, while the activities of mitochondrial oxidative enzymes, such as complex I and complex V, were significantly decreased. Furthermore, SIRT3 deficiency accelerated the Ang II-induced shift from slow-twitch towards fast-twitch fibres. Similarly, the three major rate-limiting enzymes in the glycolytic pathway, hexokinase 2 (HK2), phosphofructokinase-1(PFK) and pyruvate kinase (PK), were upregulated in Ang II-treated SIRT3 KO mice. Conclusion: These studies indicate that SIRT3 deficiency augmented Ang II-induced fibre-type shifting and metabolic reprogramming.
Collapse
Affiliation(s)
- Jianheng Zheng
- Key Laboratory of State General Administration of Sport, Shanghai Research Institute of Sports Science , Shanghai, China
| | - Jing Gao
- State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Department of Hypertension Ruijin Hospital, Shanghai Jiaotong University School of Medicine , Shanghai, China
| | - Qiuping Zhang
- Key Laboratory of State General Administration of Sport, Shanghai Research Institute of Sports Science , Shanghai, China
| | - Xiahong Wu
- Key Laboratory of State General Administration of Sport, Shanghai Research Institute of Sports Science , Shanghai, China
| | - Weili Shen
- State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Department of Hypertension Ruijin Hospital, Shanghai Jiaotong University School of Medicine , Shanghai, China
| | - Mengwei Sun
- Key Laboratory of State General Administration of Sport, Shanghai Research Institute of Sports Science , Shanghai, China
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Abreu-Vieira G, Sardjoe Mishre ASD, Burakiewicz J, Janssen LGM, Nahon KJ, van der Eijk JA, Riem TT, Boon MR, Dzyubachyk O, Webb AG, Rensen PCN, Kan HE. Human Brown Adipose Tissue Estimated With Magnetic Resonance Imaging Undergoes Changes in Composition After Cold Exposure: An in vivo MRI Study in Healthy Volunteers. Front Endocrinol (Lausanne) 2019; 10:898. [PMID: 31998233 PMCID: PMC6964318 DOI: 10.3389/fendo.2019.00898] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/09/2019] [Indexed: 01/02/2023] Open
Abstract
Aim: Magnetic resonance imaging (MRI) is increasingly being used to evaluate brown adipose tissue (BAT) function. Reports on the extent and direction of cold-induced changes in MRI fat fraction and estimated BAT volume vary between studies. Here, we aimed to explore the effect of different fat fraction threshold ranges on outcomes measured by MRI. Moreover, we aimed to investigate the effect of cold exposure on estimated BAT mass and energy content. Methods: The effects of cold exposure at different fat fraction thresholding levels were analyzed in the supraclavicular adipose depot of nine adult males. MRI data were reconstructed, co-registered and analyzed in two ways. First, we analyzed cold-induced changes in fat fraction, T2* relaxation time, volume, mass, and energy of the entire supraclavicular adipose depot at different fat fraction threshold levels. As a control, we assessed fat fraction differences of deltoid subcutaneous adipose tissue (SAT). Second, a local analysis was performed to study changes in fat fraction and T2* on a voxel-level. Thermoneutral and post-cooling data were compared using paired-sample t-tests (p < 0.05). Results: Global analysis unveiled that the largest cold-induced change in fat fraction occurred within a thermoneutral fat fraction range of 30-100% (-3.5 ± 1.9%), without changing the estimated BAT volume. However, the largest cold-induced changes in estimated BAT volume were observed when applying a thermoneutral fat fraction range of 70-100% (-3.8 ± 2.6%). No changes were observed for the deltoid SAT fat fractions. Tissue energy content was reduced from 126 ± 33 to 121 ± 30 kcal, when using a 30-100% fat fraction range, and also depended on different fat fraction thresholds. Voxel-wise analysis showed that while cold exposure changed the fat fraction across nearly all thermoneutral fat fractions, decreases were most pronounced at high thermoneutral fat fractions. Conclusion: Cold-induced changes in fat fraction occurred over the entire range of thermoneutral fat fractions, and were especially found in lipid-rich regions of the supraclavicular adipose depot. Due to the variability in response between lipid-rich and lipid-poor regions, care should be taken when applying fat fraction thresholds for MRI BAT analysis.
Collapse
Affiliation(s)
- Gustavo Abreu-Vieira
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Aashley S. D. Sardjoe Mishre
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Jedrzej Burakiewicz
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Laura G. M. Janssen
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Kimberly J. Nahon
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Jari A. van der Eijk
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Titia T. Riem
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Mariëtte R. Boon
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Oleh Dzyubachyk
- Division of Image Processing (LKEB), Department of Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Andrew G. Webb
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Patrick C. N. Rensen
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Hermien E. Kan
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
- *Correspondence: Hermien E. Kan
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Identification of an optimal threshold for detecting human brown adipose tissue using receiver operating characteristic analysis of IDEAL MRI fat fraction maps. Magn Reson Imaging 2018; 51:61-68. [PMID: 29704560 DOI: 10.1016/j.mri.2018.04.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/30/2018] [Accepted: 04/24/2018] [Indexed: 01/23/2023]
Abstract
PURPOSE Lower fat fraction (FF) in brown adipose tissue (BAT) than white adipose tissue (WAT) has been exploited using Dixon-based Magnetic Resonance Imaging (MRI) to differentiate these tissues in rodents, human infants and adults. We aimed to determine whether an optimal FF threshold could be determined to differentiate between BAT and WAT in adult humans in vivo. METHODS Sixteen volunteers were recruited (9 females, 7 males; 44.2 ± 19.2 years) based on BAT uptake on 18F-FDG PET/CT. Axial 3-echo TSE IDEAL sequences were acquired (TR(ms)/TE(ms)/matrix/NEX/FoV(cm) = 440/10.7-11.1/512 × 512/3/30-40), of the neck/upper thorax on a 3T HDxt MRI scanner (GE Medical Systems, Milwaukee, USA), and FF maps generated from the resulting water- and fat-only images. BAT depots were delineated on PET/CT based on standardized uptake values (SUV) >2.5 g/ml, and transposed onto FF maps. WAT depots were defined manually within subcutaneous fat. Receiver operating characteristic (ROC) analyses were performed, and optimal thresholds for differentiating BAT and WAT determined for each subject using Youden's J statistic. RESULTS There was large variation in optimal FF thresholds to differentiate BAT and WAT between subjects (0.68-0.85), with great variation in sensitivity (0.26-0.84) and specificity (0.62-0.99). FF was excellent or good at separating BAT and WAT in four cases (area under the curve [AUC] 0.84-0.92), but poor in 10 (AUC 0.25-0.68). CONCLUSION Although this technique was effective at differentiating BAT and WAT in some cases, no universal cut-off could be identified to reliably differentiate BAT and WAT in vivo in adult humans on the basis of FF.
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
Franssens BT, Hoogduin H, Leiner T, van der Graaf Y, Visseren FLJ. Relation between brown adipose tissue and measures of obesity and metabolic dysfunction in patients with cardiovascular disease. J Magn Reson Imaging 2017; 46:497-504. [PMID: 28130811 DOI: 10.1002/jmri.25594] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/15/2016] [Indexed: 01/21/2023] Open
Abstract
PURPOSE To evaluate whether brown adipose tissue (BAT) is present in middle-aged patients with cardiovascular comorbidities and to quantify how BAT presence associates with obesity and metabolic dysfunction. MATERIALS AND METHODS Supraclavicular and subcutaneous adipose tissue fat-signal-fraction (FF) was determined with 1.5T water-fat magnetic resonance imaging (MRI) in 50 patients with coronary artery disease, cerebrovascular disease, or peripheral artery disease. The association between BAT presence, as measured by a higher FF difference between supraclavicular and subcutaneous adipose tissue, and obesity and metabolic dysfunction was quantified using multivariable linear regression. RESULTS Supraclavicular adipose tissue displays a lower FF of 82.6% (interquartile range [IQR] 78.8-84.3) compared to 90.2% (IQR 87.3-91.9) in subcutaneous white adipose tissue (WAT, P < 0.0001). BAT presence was associated with less obesity and metabolic dysfunction. For example, 1 SD lower waist circumference (11.7 cm), 1 SD lower triglycerides (1.0 mmol/L), and absence of metabolic syndrome and type 2 diabetes were associated with 1.1% (95% confidence interval [CI] 0.1; 2.0), 1.1% (95% CI 0.1; 2.0), 2.1% (95% CI 0.1; 4.1), and 4.1% (95% CI 0.1; 7.1) higher FF difference between supraclavicular adipose tissue and subcutaneous WAT, respectively. CONCLUSION Supraclavicular adipose tissue has BAT characteristics in adult patients with clinical manifest cardiovascular disease and BAT presence is associated with less obesity and a more favorable metabolic profile. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:497-504.
Collapse
Affiliation(s)
- Bas T Franssens
- Department of Vascular Medicine, University Medical Center Utrecht, the Netherlands
| | - Hans Hoogduin
- Department of Radiology, University Medical Center Utrecht, the Netherlands
| | - Tim Leiner
- Department of Radiology, University Medical Center Utrecht, the Netherlands
| | - Yolanda van der Graaf
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, the Netherlands
| | - Frank L J Visseren
- Department of Vascular Medicine, University Medical Center Utrecht, the Netherlands
| |
Collapse
|
12
|
Hylander BL, Eng JWL, Repasky EA. The Impact of Housing Temperature-Induced Chronic Stress on Preclinical Mouse Tumor Models and Therapeutic Responses: An Important Role for the Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1036:173-189. [PMID: 29275472 DOI: 10.1007/978-3-319-67577-0_12] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In the last 10-15 years, there has been a recognition that the catecholamines (norepinephrine, NE, and epinephrine, Epi) released by the sympathetic nervous system under stressful conditions promote tumor growth through a variety of mechanisms. Tumors recruit autonomic nerves during their development and NE is then released locally in the tumor microenvironment (TME). Acting through adrenergic receptors present on a variety of cells in the TME, NE and Epi induce proliferation, resistance to apoptosis, epithelial to mesenchymal transition, metastasis of tumor cells, angiogenesis, and inflammation in the TME. These pre-clinical studies have been conducted in mouse models whose care and housing parameters are outlined in "The Guide for the Care and Use of Laboratory Animals [1]. In particular, the Guide mandates that mice be housed at standardized sub-thermoneutral temperatures; however, this causes a state of chronic cold-stress and elevated levels of NE. Although mice are able to maintain a normal body temperature when kept at these cool temperatures, it is becoming clear that this cold-stress is sufficient to activate physiological changes which affect experimental outcomes. We find that when mice are housed under standard, sub-thermoneutral temperatures (~22 °C, ST), tumor growth is significantly greater than when mice are housed at thermoneutrality (~30 °C TT). We also find that the anti-tumor immune response is suppressed at ST and this immunosuppression can be reversed by housing mice at TT or by administration of propranolol (a β-adrenergic receptor antagonist) to mice housed at ST. Furthermore, at ST tumors are more resistant to therapy and can also be sensitized to cytotoxic therapies by housing mice at TT or by treating mice with propranolol. The implications of these observations are particularly relevant to the way in which experiments conducted in preclinical models are interpreted and the findings implemented in the clinic. It may be that the disappointing failure of many new therapies to fulfill their promise in the clinic is related to an incomplete preclinical assessment in mouse models. Further, an expanded understanding of the efficacy of a therapy alone or in combination obtained by testing under a wider range of conditions would better predict how patients, who are under various levels of stress, might respond in a clinical setting. This may be particularly important to consider since we now appreciate that long term outcome of many therapies depends on eliciting an immune response.It is clear that the outcome of metabolic experiments, immunological investigations and therapeutic efficacy testing in tumors of mice housed at ST is restricted and expanding these experiments to include results obtained at TT may provide us with valuable information that would otherwise be overlooked.
Collapse
Affiliation(s)
- Bonnie L Hylander
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Jason W-L Eng
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY, USA
| | | |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Smith DL, Yarar-Fisher C. Contributors to Metabolic Disease Risk Following Spinal Cord Injury. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2016; 4:190-199. [PMID: 29276654 PMCID: PMC5737009 DOI: 10.1007/s40141-016-0124-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Spinal cord injury (SCI) induced changes in neurological function have significant impact on the metabolism and subsequent metabolic-related disease risk in injured individuals. This metabolic-related disease risk relationship is differential depending on the anatomic level and severity of the injury, with high level anatomic injuries contributing a greater risk of glucose and lipid dysregulation resulting in type 2 diabetes and cardiovascular disease risk elevation. Although alterations in body composition, particularly excess adiposity and its anatomical distribution in the visceral depot or ectopic location in non-adipose organs, is known to significantly contribute to metabolic disease risk, changes in fat mass and fat-free mass do not fully account for this elevated disease risk in subjects with SCI. There are other negative adaptations in body composition including reductions in skeletal muscle mass and alterations in muscle fiber type, in addition to significant reduction in physical activity, that contribute to a decline in metabolic rate and increased metabolic disease risk following SCI. Recent studies in adult humans suggest cold- and diet-induced thermogenesis through brown adipose tissue metabolism may be important for energy balance and substrate metabolism, and particularly sensitive to sympathetic nervous signaling. Considering the alterations that occur in the autonomic nervous system (SNS) (sympathetic and parasympathetic) following a SCI, significant dysfunction of brown adipose function is expected. This review will highlight metabolic alterations following SCI and integrate findings from brown adipose tissue studies as potential new areas of research to pursue.
Collapse
Affiliation(s)
- Daniel L. Smith
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham AL, 35294 USA
- Nathan Shock Center of Excellence in the Basic Biology of Aging, University of Alabama at Birmingham, Birmingham AL, 35294 USA
- Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham AL, 35294 USA
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham AL, 35294 USA
| | - Ceren Yarar-Fisher
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham AL, 35294 USA
- Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham, Birmingham AL, 35294 USA
- Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham AL, 35294 USA
| |
Collapse
|
15
|
Kasza I, Hernando D, Roldán-Alzate A, Alexander CM, Reeder SB. Thermogenic profiling using magnetic resonance imaging of dermal and other adipose tissues. JCI Insight 2016; 1:e87146. [PMID: 27668285 DOI: 10.1172/jci.insight.87146] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Dermal white adipose tissue (dWAT) was recently recognized for its potential to modify whole body metabolism. Here, we show that dWAT can be quantified using a high-resolution, fat-specific magnetic resonance imaging (MRI) technique. Noninvasive MRI has been used to describe adipocyte depots for many years; the MRI technique we describe uses an advanced fat-specific method to measure the thickness of dWAT, together with the total volume of WAT and the relative activation/fat depletion of brown adipose tissues (BAT). Since skin-embedded adipocytes may provide natural insulation, they provide an important counterpoint to the activation of thermogenic brown and beige adipose tissues, whereby these distinct depots are functionally interrelated and require simultaneous assay. This method was validated using characterized mouse cohorts of a lipodystrophic, dWAT-deficient strain (syndecan-1 KO) and 2 obese models (diet-induced obese mice and genetically obese animals, ob/ob). Using a preliminary cohort of normal human subjects, we found the thickness of skin-associated fat varied 8-fold, from 0.13-1.10 cm; on average, this depot is calculated to weigh 8.8 kg.
Collapse
Affiliation(s)
| | | | | | | | - Scott B Reeder
- Department of Radiology.,Department of Medical Physics.,Department of Biomedical Engineering.,Department of Medicine, and.,Department of Emergency Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| |
Collapse
|
16
|
Hylander BL, Repasky EA. Thermoneutrality, Mice, and Cancer: A Heated Opinion. Trends Cancer 2016; 2:166-175. [PMID: 28741570 DOI: 10.1016/j.trecan.2016.03.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/31/2022]
Abstract
The 'mild' cold stress caused by standard sub-thermoneutral housing temperatures used for laboratory mice in research institutes is sufficient to significantly bias conclusions drawn from murine models of several human diseases. We review the data leading to this conclusion, discuss the implications for research and suggest ways to reduce problems in reproducibility and experimental transparency caused by this housing variable. We have found that these cool temperatures suppress endogenous immune responses, skewing tumor growth data and the severity of graft versus host disease, and also increase the therapeutic resistance of tumors. Owing to the potential for ambient temperature to affect energy homeostasis as well as adrenergic stress, both of which could contribute to biased outcomes in murine cancer models, housing temperature should be reported in all publications and considered as a potential source of variability in results between laboratories. Researchers and regulatory agencies should work together to determine whether changes in housing parameters would enhance the use of mouse models in cancer research, as well as for other diseases. Finally, for many years agencies such as the National Cancer Institute (NCI) have encouraged the development of newer and more sophisticated mouse models for cancer research, but we believe that, without an appreciation of how basic murine physiology is affected by ambient temperature, even data from these models is likely to be compromised.
Collapse
Affiliation(s)
- Bonnie L Hylander
- Roswell Park Cancer Institute, Department of Immunology, Elm and Carlton Streets, Buffalo, NY 14263-0001, USA
| | - Elizabeth A Repasky
- Roswell Park Cancer Institute, Department of Immunology, Elm and Carlton Streets, Buffalo, NY 14263-0001, USA.
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Franssens BT, Eikendal AL, Leiner T, van der Graaf Y, Visseren FLJ, Hoogduin JM. Reliability and agreement of adipose tissue fat fraction measurements with water-fat MRI in patients with manifest cardiovascular disease. NMR IN BIOMEDICINE 2016; 29:48-56. [PMID: 26620447 DOI: 10.1002/nbm.3444] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 10/13/2015] [Accepted: 10/19/2015] [Indexed: 06/05/2023]
Abstract
The supraclavicular fat depot is known for brown adipose tissue presence. To unravel adipose tissue physiology and metabolism, high quality and reproducible imaging is required. In this study we quantified the reliability and agreement of MRI fat fraction measurements in supraclavicular and subcutaneous adipose tissue of 25 adult patients with clinically manifest cardiovascular disease. MRI fat fraction measurements were made under ambient temperature conditions using a vendor supplied mDixon chemical-shift water-fat multi-echo pulse sequence at 1.5 T field strength. Supraclavicular fat fraction reliability (intraclass correlation coefficientagreement , ICCagreement ) was 0.97 for test-retest, 0.95 for intra-observer and 0.56 for inter-observer measurements, which increased to 0.88 when ICCconsistency was estimated. Supraclavicular fat fraction agreement displayed mean differences of 0.5% (limit of agreement (LoA) -1.7 to 2.6) for test-retest, -0.5% (LoA -2.9 to 2.0) for intra-observer and 5.6% (LoA 0.4 to 10.8) for inter-observer measurements. Median fat fraction in supraclavicular adipose tissue was 82.5% (interquartile range (IQR) 78.6-84.0) and 89.7% (IQR 87.2-91.5) in subcutaneous adipose tissue (p < 0.0001). In conclusion, water-fat MRI has good reliability and agreement to measure adipose tissue fat fraction in patients with manifest cardiovascular disease. These findings enable research on determinants of fat fraction and enable longitudinal monitoring of fat fraction within adipose tissue depots. Interestingly, even in adult patients with manifest cardiovascular disease, supraclavicular adipose tissue has a lower fat fraction compared with subcutaneous adipose tissue, suggestive of distinct morphologic characteristics, such as brown adipose tissue.
Collapse
Affiliation(s)
- Bas T Franssens
- Department of Vascular Medicine, University Medical Center Utrecht, The Netherlands
| | - Anouk L Eikendal
- Department of Radiology, University Medical Center Utrecht, The Netherlands
| | - Tim Leiner
- Department of Radiology, University Medical Center Utrecht, The Netherlands
| | - Yolanda van der Graaf
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, The Netherlands
| | - Frank L J Visseren
- Department of Vascular Medicine, University Medical Center Utrecht, The Netherlands
| | - J M Hoogduin
- Department of Radiology, University Medical Center Utrecht, The Netherlands
| |
Collapse
|
19
|
Romu T, Elander L, Leinhard OD, Lidell ME, Betz MJ, Persson A, Enerbäck S, Borga M. Characterization of brown adipose tissue by water-fat separated magnetic resonance imaging. J Magn Reson Imaging 2015; 42:1639-45. [PMID: 25914213 DOI: 10.1002/jmri.24931] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/09/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND To evaluate the possibility of quantifying brown adipose tissue (BAT) volume and fat concentration with a high resolution, long echo time, dual-echo Dixon imaging protocol. METHODS A 0.42 mm isotropic resolution water-fat separated MRI protocol was implemented by using the second opposite-phase echo and third in-phase echo. Fat images were calibrated with regard to the intensity of nearby white adipose tissue (WAT) to form relative fat content (RFC) images. To evaluate the ability to measure BAT volume and RFC contrast dynamics, rats were divided into two groups that were kept at 4° or 22°C for 5 days. The rats were then scanned in a 70 cm bore 3.0 Tesla MRI scanner and a human dual energy CT. Interscapular, paraaortal, and perirenal BAT (i/pa/pr-BAT) depots as well as WAT and muscle were segmented in the MRI and CT images. Biopsies were collected from the identified BAT depots. RESULTS The biopsies confirmed that the three depots identified with the RFC images consisted of BAT. There was a significant linear correlation (P < 0.001) between the measured RFC and the Hounsfield units from DECT. Significantly lower iBAT RFC (P = 0.0064) and significantly larger iBAT and prBAT volumes (P = 0.0017) were observed in the cold stimulated rats. CONCLUSION The calibrated Dixon images with RFC scaling can depict BAT and be used to measure differences in volume, and fat concentration, induced by cold stimulation. The high correlation between RFC and HU suggests that the fat concentration is the main RFC image contrast mechanism.
Collapse
Affiliation(s)
- Thobias Romu
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Louise Elander
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Linköping University, Department of Anaesthesiology and Intensive Care and Department of Medical and Health Sciences, Norrköping, 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
| | - Martin E Lidell
- Department of Medical and Clinical Genetics, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Matthias J Betz
- Department of Medical and Clinical Genetics, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Endocrine Research Unit, Medizinische Klinik und Poliklinik IV, Klinikum der Ludwig Maximilians University (LMU), Munich, Germany
| | - Anders Persson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Department of Radiation Physics and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Sven Enerbäck
- Department of Medical and Clinical Genetics, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Magnus Borga
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| |
Collapse
|
20
|
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.
Collapse
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
Collapse
|
21
|
Grimpo K, Völker MN, Heppe EN, Braun S, Heverhagen JT, Heldmaier G. Brown adipose tissue dynamics in wild-type and UCP1-knockout mice: in vivo insights with magnetic resonance. J Lipid Res 2014; 55:398-409. [PMID: 24343897 PMCID: PMC3934725 DOI: 10.1194/jlr.m042895] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 12/06/2013] [Indexed: 01/12/2023] Open
Abstract
We used noninvasive magnetic resonance imaging (MRI) and magnetic resonance spectroscopy to compare interscapular brown adipose tissue (iBAT) of wild-type (WT) and uncoupling protein 1 (UCP1)-knockout mice lacking UCP1-mediated nonshivering thermogenesis (NST). Mice were sequentially acclimated to an ambient temperature of 30°C, 18°C, and 5°C. We detected a remodeling of iBAT and a decrease in its lipid content in all mice during cold exposure. Ratios of energy-rich phosphates (ATP/ADP, phosphocreatine/ATP) in iBAT were maintained stable during noradrenergic stimulation of thermogenesis in cold- and warm-adapted mice and no difference between the genotypes was observed. As free fatty acids (FFAs) serve as fuel for thermogenesis and activate UCP1 for uncoupling of oxidative phosphorylation, brown adipose tissue is considered to be a main acceptor and consumer of FFAs. We measured a major loss of FFAs from iBAT during noradrenergic stimulation of thermogenesis. This mobilization of FFAs was observed in iBAT of WT mice as well as in mice lacking UCP1. The high turnover and the release of FFAs from iBAT suggests an enhancement of lipid metabolism, which in itself contributes to the sympathetically activated NST and which is independent from uncoupled respiration mediated by UCP1. Our study demonstrates that MRI, besides its potential for visualizing and quantification of fat tissue, is a valuable tool for monitoring functional in vivo processes like lipid and phosphate metabolism during NST.
Collapse
Affiliation(s)
- Kirsten Grimpo
- Faculty of Biology, Department of Animal Physiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Maximilian N. Völker
- Faculty of Medicine, Department of Diagnostic Radiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Eva N. Heppe
- Faculty of Biology, Department of Animal Physiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Steve Braun
- Faculty of Medicine, Department of Diagnostic Radiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Johannes T. Heverhagen
- Institute for Diagnostic, Interventional, and Paediatric Radiology, University Hospital Inselspital, Bern, Switzerland
| | - Gerhard Heldmaier
- Faculty of Biology, Department of Animal Physiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| |
Collapse
|
22
|
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.
Collapse
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
| |
Collapse
|
23
|
Hu HH, Wu TW, Yin L, Kim MS, Chia JM, Perkins TG, Gilsanz V. MRI detection of brown adipose tissue with low fat content in newborns with hypothermia. Magn Reson Imaging 2013; 32:107-17. [PMID: 24239336 DOI: 10.1016/j.mri.2013.10.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 08/05/2013] [Accepted: 10/08/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE To report the observation of brown adipose tissue (BAT) with low fat content in neonates with hypoxic-ischemic encephalopathy (HIE) after they have undergone hypothermia therapy. MATERIALS AND METHODS The local ethics committee approved the imaging study. Ten HIE neonates (3 males, 7 females, age range: 2-3days) were studied on a 3-T MRI system using a low-flip-angle (3°) six-echo proton-density-weighted chemical-shift-encoded water-fat pulse sequence. Fat-signal fraction (FF) measurements of supraclavicular and interscapular (nape) BAT and adjacent subcutaneous white adipose tissues (WAT) were compared to those from five non-HIE neonates, two recruited for the present investigation and three from a previous study. RESULTS In HIE neonates, the FF range for the supraclavicular, interscapular, and subcutaneous regions was 10.3%-29.9%, 28.0%-57.9%, and 62.6%-88.0%, respectively. In non-HIE neonates, the values were 23.7%-42.2% (p=0.01), 45.4%-59.5% (p=0.06), and 67.8%-86.3% (p=0.38), respectively. On an individual basis, supraclavicular BAT FF was consistently the lowest, interscapular BAT values were higher, and subcutaneous WAT values were the highest (p<0.01). CONCLUSION We speculate that hypothermia therapy in HIE neonates likely promotes BAT-mediated non-shivering thermogenesis, which subsequently leads to a depletion of the tissue's intracellular fat stores. We believe that this is consequently reflected in lower FF values, particularly in the supraclavicular BAT depot, in contrast to non-HIE neonates.
Collapse
Affiliation(s)
- Houchun H Hu
- Radiology, Children's Hospital Los Angeles, Los Angeles, CA, USA.
| | - Tai-Wei Wu
- Neonatology, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Larry Yin
- Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Mimi S Kim
- Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | | | | | - Vicente Gilsanz
- Radiology, Children's Hospital Los Angeles, Los Angeles, CA, USA; Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, USA
| |
Collapse
|
24
|
Branca RT, Zhang L, Warren WS, Auerbach E, Khanna A, Degan S, Ugurbil K, Maronpot R. In vivo noninvasive detection of Brown Adipose Tissue through intermolecular zero-quantum MRI. PLoS One 2013; 8:e74206. [PMID: 24040203 PMCID: PMC3769256 DOI: 10.1371/journal.pone.0074206] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/27/2013] [Indexed: 12/12/2022] Open
Abstract
The recent discovery of active Brown Adipose Tissue (BAT) in adult humans has opened new avenues for obesity research and treatment, as reduced BAT activity seem to be implicated in human energy imbalance, diabetes, and hypertension. However, clinical applications are currently limited by the lack of non-invasive tools for measuring mass and function of this tissue in humans. Here we present a new magnetic resonance imaging method based on the normally invisible intermolecular multiple-quantum coherence 1H MR signal. This method, which doesn’t require special hardware modifications, can be used to overcome partial volume effect, the major limitation of MR-based approaches that are currently being investigated for the detection of BAT in humans. With this method we can exploit the characteristic cellular structure of BAT to selectively image it, even when (as in humans) it is intimately mixed with other tissues. We demonstrate and validate this method in mice using PET scans and histology. We compare this methodology with conventional 1H MR fat fraction methods. Finally, we investigate its feasibility for the detection of BAT in humans.
Collapse
Affiliation(s)
- Rosa T. Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
| | - Le Zhang
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Applied Science and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Warren S. Warren
- Department of Chemistry, Duke University, Durham, North Carolina, United States of America
| | - Edward Auerbach
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Arjun Khanna
- Department of Chemistry, Duke University, Durham, North Carolina, United States of America
| | - Simone Degan
- Department of Chemistry, Duke University, Durham, North Carolina, United States of America
| | - Kamil Ugurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Robert Maronpot
- Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina, United States of America
| |
Collapse
|
25
|
Yang Y, Smith DL, Hu HH, Zhai G, Nagy TR. Chemical-shift water-fat MRI of white adipose depots: inability to resolve cell size differences. INTERNATIONAL JOURNAL OF BODY COMPOSITION RESEARCH 2013; 11:9-16. [PMID: 23667321 PMCID: PMC3649013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PURPOSE Adipocyte cell size varies among individuals and importantly, is inversely correlated with insulin sensitivity, and modifiable by weight loss or pharmaceutical agents. However, there are no non-invasive, in vivo methods for adipocyte cell size determination. Here we apply Chemical-Shift Water-Fat MRI to in vivo measures of subcutaneous (inguinal) and visceral (gonadal) white adipose tissue (WAT) to determine whether the fat-signal fraction (FF) is a sensitive indicator of adipocyte cell size. MATERIALS AND METHODS C57BL/6J male mice (8 weeks old) were singly housed and fed a low-fat diet, high-fat diet or very high-fat diet (n = 16 or 15/group) for 8 weeks. Food intake, body weight and composition were measured; CS-MRI was performed on a 9.4 Tesla Bruker magnet with respiratory gating and anesthesia. Histology was acquired for gonadal WAT; both gonadal and inguinal WAT were fixed with osmium tetroxide and then measured through Image J for cell size. RESULTS Mice fed with higher fat content diets gained significantly more body weight, fat and lean mass while maintaining higher energy intakes over the 8 weeks. There was no significant difference in fat fraction for either gonadal (P = 0.1295) or inguinal (P = 0.4704) WAT among the three groups, despite significantly larger adipocytes (P <0.0001) in mice on high fat diets. CONCLUSION Although diet-induced obesity significantly increased the amount of fat mass, as well as mean and overall white adipocyte cell size, the CS-MRI measured fat fraction between groups were not significantly different. These results do not support the utility of CS-MRI measured FF for in vivo determination of adipocyte cell size.
Collapse
Affiliation(s)
- Yongbin Yang
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel L. Smith
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
- Diabetes Research Training Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Houchun H. Hu
- Department of Radiology, Children’s Hospital Los Angeles, University of Southern California, Los Angeles, CA, USA
| | - Guihua Zhai
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tim R. Nagy
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
- Diabetes Research Training Center, University of Alabama at Birmingham, Birmingham, AL, USA
| |
Collapse
|