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Zhao JY, Zhou LJ, Ma KL, Hao R, Li M. MHO or MUO? White adipose tissue remodeling. Obes Rev 2024; 25:e13691. [PMID: 38186200 DOI: 10.1111/obr.13691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 11/14/2023] [Accepted: 11/19/2023] [Indexed: 01/09/2024]
Abstract
In this review, we delve into the intricate relationship between white adipose tissue (WAT) remodeling and metabolic aspects in obesity, with a specific focus on individuals with metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO). WAT is a highly heterogeneous, plastic, and dynamically secreting endocrine and immune organ. WAT remodeling plays a crucial role in metabolic health, involving expansion mode, microenvironment, phenotype, and distribution. In individuals with MHO, WAT remodeling is beneficial, reducing ectopic fat deposition and insulin resistance (IR) through mechanisms like increased adipocyte hyperplasia, anti-inflammatory microenvironment, appropriate extracellular matrix (ECM) remodeling, appropriate vascularization, enhanced WAT browning, and subcutaneous adipose tissue (SWAT) deposition. Conversely, for those with MUO, WAT remodeling leads to ectopic fat deposition and IR, causing metabolic dysregulation. This process involves adipocyte hypertrophy, disrupted vascularization, heightened pro-inflammatory microenvironment, enhanced brown adipose tissue (BAT) whitening, and accumulation of visceral adipose tissue (VWAT) deposition. The review underscores the pivotal importance of intervening in WAT remodeling to hinder the transition from MHO to MUO. This insight is valuable for tailoring personalized and effective management strategies for patients with obesity in clinical practice.
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Affiliation(s)
- Jing Yi Zhao
- Research Laboratory of Molecular Biology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Li Juan Zhou
- Research Laboratory of Molecular Biology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Kai Le Ma
- Research Laboratory of Molecular Biology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Rui Hao
- Research Laboratory of Molecular Biology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Min Li
- Research Laboratory of Molecular Biology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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2
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Lum FM, Chan YH, Teo TH, Becht E, Amrun SN, Teng KW, Hartimath SV, Yeo NK, Yee WX, Ang N, Torres-Ruesta AM, Fong SW, Goggi JL, Newell EW, Renia L, Carissimo G, Ng LF. Crosstalk between CD64 +MHCII + macrophages and CD4 + T cells drives joint pathology during chikungunya. EMBO Mol Med 2024; 16:641-663. [PMID: 38332201 PMCID: PMC10940729 DOI: 10.1038/s44321-024-00028-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 02/10/2024] Open
Abstract
Communications between immune cells are essential to ensure appropriate coordination of their activities. Here, we observed the infiltration of activated macrophages into the joint-footpads of chikungunya virus (CHIKV)-infected animals. Large numbers of CD64+MHCII+ and CD64+MHCII- macrophages were present in the joint-footpad, preceded by the recruitment of their CD11b+Ly6C+ inflammatory monocyte precursors. Recruitment and differentiation of these myeloid subsets were dependent on CD4+ T cells and GM-CSF. Transcriptomic and gene ontology analyses of CD64+MHCII+ and CD64+MHCII- macrophages revealed 89 differentially expressed genes, including genes involved in T cell proliferation and differentiation pathways. Depletion of phagocytes, including CD64+MHCII+ macrophages, from CHIKV-infected mice reduced disease pathology, demonstrating that these cells play a pro-inflammatory role in CHIKV infection. Together, these results highlight the synergistic dynamics of immune cell crosstalk in driving CHIKV immunopathogenesis. This study provides new insights in the disease mechanism and offers opportunities for development of novel anti-CHIKV therapeutics.
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Affiliation(s)
- Fok-Moon Lum
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore.
| | - Yi-Hao Chan
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Teck-Hui Teo
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Etienne Becht
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research, Singapore, 138648, Singapore
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Siti Naqiah Amrun
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Karen Ww Teng
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Siddesh V Hartimath
- Institute of Bioengineering and Bioimaging (IBB), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Nicholas Kw Yeo
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Wearn-Xin Yee
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Nicholas Ang
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Anthony M Torres-Ruesta
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Siew-Wai Fong
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Julian L Goggi
- Institute of Bioengineering and Bioimaging (IBB), Agency for Science, Technology and Research, Singapore, 138648, Singapore
| | - Evan W Newell
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research, Singapore, 138648, Singapore
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Laurent Renia
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research, Singapore, 138648, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Guillaume Carissimo
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Lisa Fp Ng
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research, Singapore, 138648, Singapore.
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.
- National Institute of Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, L69 7BE, UK.
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 7ZX, UK.
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Abbasi M, Fan Z, Dawson JA, Wang S. Anti-obesity and metabolic benefits of metformin: Comparison of different delivery routes. J Drug Deliv Sci Technol 2024; 91:105110. [PMID: 38188941 PMCID: PMC10768944 DOI: 10.1016/j.jddst.2023.105110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Obesity is a severe public health problem. Healthy lifestyle interventions are commonly recommended for fighting obesity. But they are hard to follow and have low efficacy. Pharmacotherapy and surgery are of high efficacy but are beset with side effects. Browning subcutaneous white adipose tissue (WAT) is a practical and efficient approach for combating obesity. Metformin, a commonly used FDA-approved antidiabetic drug, is potent to induce browning of WAT through phosphorylation and activation of AMP-activated protein kinase. However, oral administration of metformin has low oral bioavailability, fast renal clearance, and low target specificity that limit metformin's application in browning WAT. Local and transdermal delivery of metformin directly to subcutaneous WAT using injection or microneedle (MN) in combination with iontophoresis (INT) may solve these problems. In this paper, we administered metformin to C57BL/6J obese mice using the following three routes: transdermal delivery (MN and INT), local injection into inguinal WAT (IgWAT, a type of subcutaneous WAT in mice), and oral gavage. The anti-obesity and metabolic effects of metformin via these delivery routes were determined and compared. As compared to local IgWAT injection and oral gavage delivery, transdermal delivery of metformin using MN and INT resulted in 9% lower body weight and 7% decrease in body fat% accompanied by improved energy metabolism and decreased inflammation through browning IgWAT in obese C57BL/6J mice. Transdermal delivery of metformin using MN and INT is an effective approach in browning subcutaneous WAT for combating obesity and improving metabolic health.
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Affiliation(s)
- Mehrnaz Abbasi
- Department of Nutritional Sciences, Texas Tech University, Lubbock, Texas 79409, USA
- College of Human Sciences, Auburn University, Auburn, AL, 36830, USA
| | - Zhaoyang Fan
- Department of Nutritional Sciences, Texas Tech University, Lubbock, Texas 79409, USA
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85281, USA
| | - John A. Dawson
- Department of Nutritional Sciences, Texas Tech University, Lubbock, Texas 79409, USA
- Department of Economics, Applied Statistics, and International, New Mexico State University, Las Cruces, New Mexico 88003, USA
| | - Shu Wang
- Department of Nutritional Sciences, Texas Tech University, Lubbock, Texas 79409, USA
- College of Health Solutions, Arizona State University, Phoenix, Arizona, 85004, USA
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Holmes LR, Garside JC, Frank J, Livingston E, Snyder J, Abu Khalaf N, Yuan H, Branca RT. In-vivo detection of white adipose tissue browning: a multimodality imaging approach. Sci Rep 2023; 13:15485. [PMID: 37726379 PMCID: PMC10509182 DOI: 10.1038/s41598-023-42537-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/11/2023] [Indexed: 09/21/2023] Open
Abstract
Detection and differentiation of brown fat in humans poses several challenges, as this tissue is sparse and often mixed with white adipose tissue. Non-invasive detection of beige fat represents an even greater challenge as this tissue is structurally and functionally more like white fat than brown fat. Here we used positron emission tomography with 18F-fluorodeoxyglucose, computed tomography, xenon-enhanced computed tomography, and dynamic contrast-enhanced ultrasound, to non-invasively detect functional and structural changes associated with the browning process of inguinal white fat, induced in mice by chronic stimulation with the β3-adrenergic receptor agonist CL-316243. These studies reveal a very heterogeneous increase in baseline tissue radiodensity and xenon-enhanced radiodensity, indicative of both an increase in adipocytes water and protein content as well as tissue perfusion, mostly in regions that showed enhanced norepinephrine-stimulated perfusion before CL-316243 treatment. No statistically significant increase in 18F-fluorodeoxyglucose uptake or norepinephrine-stimulated tissue perfusion were observed in the mice after the CL-316243 treatment. The increase in tissue-water content and perfusion, along with the negligible increase in the tissue glucose uptake and norepinephrine-stimulated perfusion deserve more attention, especially considering the potential metabolic role that this tissue may play in whole body metabolism.
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Affiliation(s)
- Leah R Holmes
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - John C Garside
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jonathan Frank
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Eric Livingston
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jonas Snyder
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Nada Abu Khalaf
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Hong Yuan
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Rosa T Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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Ricci M, De Feo MS, Granese GM, Frantellizzi V, Carabellese B, Lubrano E, Cimini A. 18F-FDG PET/CT technology for the assessment of brown adipose tissue: an updated review. Expert Rev Med Devices 2023; 20:1143-1156. [PMID: 37965719 DOI: 10.1080/17434440.2023.2283618] [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: 05/30/2023] [Accepted: 11/10/2023] [Indexed: 11/16/2023]
Abstract
INTRODUCTION This review provides an update of 18 F-fluorodeoxyglucose ([18F] FDG) for Brown adipose tissue (BAT) activity quantification, whose role is not completely understood. AREAS COVERED We conducted an unstructured search of the literature for any studies employing the [18F] FDG PET in BAT assessment. We explored BAT quantification both in healthy individuals and in different pathologies, after cold exposure and as a metabolic biomarker. The assessment of possible BAT modulators by using [18F] FDG PET is shown. Further PET tracers and novel developments for BAT assessments are also described. EXPERT OPINION Further PET tracers and imaging modalities are under investigation, but the [18F] FDG PET is currently the method of choice for the evaluation of BAT and further multicentric trials are needed for a better understanding of the BAT physiopathology, also after cold stimuli. The modulation of BAT activity, assessed by [18F] FDG PET imaging, seems a promising tool for the management of conditions such as obesity and type 2 diabetes. Moreover, an interesting possible correlation of BAT activation with prognostic [18F] FDG PET indices in cancer patients should be assessed with further multicentric trials.
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Affiliation(s)
- Maria Ricci
- Nuclear Medicine Unit, Cardarelli Hospital, Campobasso, Italy
| | - Maria Silvia De Feo
- Department of Radiological Sciences Oncology and Anatomo-Pathology, Sapienza University of Rome, Rome, Italy
| | - Giorgia Maria Granese
- Department of Radiological Sciences Oncology and Anatomo-Pathology, Sapienza University of Rome, Rome, Italy
| | - Viviana Frantellizzi
- Department of Radiological Sciences Oncology and Anatomo-Pathology, Sapienza University of Rome, Rome, Italy
| | | | - Ennio Lubrano
- Dipartimento di Medicina e Scienze della Salute, Università degli Studi del Molise, Italy
- Department of Development and Regeneration, Skeletal Biology and Engineering Research Center, KU Leuven, Leuven, Belgium
| | - Andrea Cimini
- Nuclear Medicine Unit, St. Salvatore Hospital, L'Aquila, Italy
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Abstract
Brown adipose tissue (BAT) displays the unique capacity to generate heat through uncoupled oxidative phosphorylation that makes it a very attractive therapeutic target for cardiometabolic diseases. Here, we review BAT cellular metabolism, its regulation by the central nervous and endocrine systems and circulating metabolites, the plausible roles of this tissue in human thermoregulation, energy balance, and cardiometabolic disorders, and the current knowledge on its pharmacological stimulation in humans. The current definition and measurement of BAT in human studies relies almost exclusively on BAT glucose uptake from positron emission tomography with 18F-fluorodeoxiglucose, which can be dissociated from BAT thermogenic activity, as for example in insulin-resistant states. The most important energy substrate for BAT thermogenesis is its intracellular fatty acid content mobilized from sympathetic stimulation of intracellular triglyceride lipolysis. This lipolytic BAT response is intertwined with that of white adipose (WAT) and other metabolic tissues, and cannot be independently stimulated with the drugs tested thus far. BAT is an interesting and biologically plausible target that has yet to be fully and selectively activated to increase the body's thermogenic response and shift energy balance. The field of human BAT research is in need of methods able to directly, specifically, and reliably measure BAT thermogenic capacity while also tracking the related thermogenic responses in WAT and other tissues. Until this is achieved, uncertainty will remain about the role played by this fascinating tissue in human cardiometabolic diseases.
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Affiliation(s)
- André C Carpentier
- Correspondence: André C. Carpentier, MD, Division of Endocrinology, Faculty of Medicine, University of Sherbrooke, 3001, 12th Ave N, Sherbrooke, Quebec, J1H 5N4, Canada.
| | - Denis P Blondin
- Division of Neurology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
| | | | - Denis Richard
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec City, Quebec, G1V 4G5, Canada
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Zhu B, Liang SH, Ran C. Imaging Brown Adipose Tissue with TSPO PET Tracers in Preclinical Animal Studies. Methods Mol Biol 2023; 2662:147-156. [PMID: 37076678 DOI: 10.1007/978-1-0716-3167-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
Brown adipose tissue (BAT) is closely associated with thermogenesis and related to numerous diseases, including type 2 diabetes, nonalcoholic fatty liver disease (NAFLD), and obesity. Using molecular imaging technologies to monitor BAT could facilitate etiology elucidation, disease diagnosis, and therapeutics development. Translocator protein (TSPO), an 18 kDa protein that mainly locates on the outer mitochondrial membrane, has been proven as a promising biomarker for monitoring BAT mass. Here, we lay out the steps for imaging BAT with TSPO PET tracer [18F]-DPA in mouse studies.
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Affiliation(s)
- Biyue Zhu
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Chongzhao Ran
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA.
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Neuroinflammation in Low-Level PM2.5-Exposed Rats Illustrated by PET via an Improved Automated Produced [18F]FEPPA: A Feasibility Study. Mol Imaging 2022; 2022:1076444. [PMID: 35903248 PMCID: PMC9328187 DOI: 10.1155/2022/1076444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 04/10/2022] [Accepted: 05/18/2022] [Indexed: 11/26/2022] Open
Abstract
Background [18F]FEPPA is a potent TSPO imaging agent that has been found to be a potential tracer for imaging neuroinflammation. In order to fulfill the demand of this tracer for preclinical and clinical studies, we have developed a one-pot automated synthesis with simplified HPLC purification of this tracer, which was then used for PET imaging of neuroinflammation in fine particulate matter- (PM2.5-) exposed rats. Results Using this automated synthesis method, the RCY of the [18F]FEPPA was 38 ± 4% (n = 17, EOB) in a synthesis time of 83 ± 8 min from EOB. The radiochemical purity and molar activities were greater than 99% and 209 ± 138 GBq/μmol (EOS, n = 15), respectively. The quality of the [18F]FEPPA synthesized by this method met the U.S. Pharmacopoeia (USP) criteria. The stability test showed that the [18F]FEPPA was stable at 21 ± 2°C for up to 4 hr after the end of synthesis (EOS). Moreover, microPET imaging showed that increased tracer activity of [18F]FEPPA in the brain of PM2.5-exposed rats (n = 6) were higher than that of normal controls (n = 6) and regional-specific. Conclusions Using the improved semipreparative HPLC purification, [18F]FEPPA has been produced in high quantity, high quality, and high reproducibility and, for the first time, used for PET imaging the effects of PM2.5 in the rat brain. It is ready to be used for imaging inflammation in various clinical or preclinical studies, especially for nearby PET centers without cyclotrons.
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Imaging Adipose Tissue Browning using Mitochondrial Complex-I Tracer [ 18F]BCPP-EF. CONTRAST MEDIA & MOLECULAR IMAGING 2022; 2022:6113660. [PMID: 35694709 PMCID: PMC9173993 DOI: 10.1155/2022/6113660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/21/2022] [Accepted: 05/19/2022] [Indexed: 01/09/2023]
Abstract
Browning of white adipose tissue (WAT) into beige adipocytes has been proposed as a strategy to tackle the ongoing obesity epidemic. Thermogenic stimuli have been investigated with the aim of converting existing white adipose tissue, primarily used for energy storage, into beige adipocytes capable of dissipating energy; however, evaluation is complicated by the dearth of noninvasive methodologies to quantify de novo beige adipocytes in WAT. Imaging with [18F]FDG is commonly used to measure brown adipose tissue (BAT) and beige adipocytes but the relationship between beige adipocytes, thermogenesis and [18F]FDG uptake is unclear. [18F]BCPP-EF, a tracer for mitochondrial complex-I (MC-I), acts as a marker of oxidative metabolism and may be useful for the detection of newly formed beige adipocytes. Mice received doses of the β3-adrenergic agonist CL-316,243 subchronically for 7 days to induce formation of beige adipocytes in inguinal white fat. PET imaging was performed longitudinally with both [18F]FDG (a marker of glycolysis) and [18F]BCPP-EF (an MC-I marker) to assess the effect of thermogenic stimulation on uptake in browning inguinal WAT and interscapular BAT. Treatment with CL-316,243 led to significant increases in both [18F]FDG and [18F]BCPP-EF in inguinal WAT. The uptake of [18F]BCPP-EF in inguinal WAT was significantly increased above control levels after 3 days of stimulation, whereas [18F]FDG only showed a significant increase after 7 days. The uptake of [18F]BCPP-EF in newly formed beige adipocytes was blocked by pretreatment with an adrenoceptor antagonist suggesting that beige adipocyte formation may be associated with the activation of MC-I. However, in BAT, uptake of [18F]BCPP-EF was unaffected by β3-adrenergic stimulation, potentially due to the high expression of MC-I. [18F]BCPP-EF can detect newly formed beige adipocytes in WAT generated after subchronic treatment with the β3-adrenergic agonist CL-316,243 and displays both higher inguinal WAT uptake and earlier detection than [18F]FDG. The MC-I tracer may be a useful tool in the evaluation of new therapeutic strategies targeting metabolic adipose tissues to tackle obesity and metabolic diseases.
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Hegi-Johnson F, Rudd S, Hicks RJ, De Ruysscher D, Trapani JA, John T, Donnelly P, Blyth B, Hanna G, Everitt S, Roselt P, MacManus MP. Imaging immunity in patients with cancer using positron emission tomography. NPJ Precis Oncol 2022; 6:24. [PMID: 35393508 PMCID: PMC8989882 DOI: 10.1038/s41698-022-00263-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 02/24/2022] [Indexed: 12/26/2022] Open
Abstract
Immune checkpoint inhibitors and related molecules can achieve tumour regression, and even prolonged survival, for a subset of cancer patients with an otherwise dire prognosis. However, it remains unclear why some patients respond to immunotherapy and others do not. PET imaging has the potential to characterise the spatial and temporal heterogeneity of both immunotherapy target molecules and the tumor immune microenvironment, suggesting a tantalising vision of personally-adapted immunomodulatory treatment regimens. Personalised combinations of immunotherapy with local therapies and other systemic therapies, would be informed by immune imaging and subsequently modified in accordance with therapeutically induced immune environmental changes. An ideal PET imaging biomarker would facilitate the choice of initial therapy and would permit sequential imaging in time-frames that could provide actionable information to guide subsequent therapy. Such imaging should provide either prognostic or predictive measures of responsiveness relevant to key immunotherapy types but, most importantly, guide key decisions on initiation, continuation, change or cessation of treatment to reduce the cost and morbidity of treatment while enhancing survival outcomes. We survey the current literature, focusing on clinically relevant immune checkpoint immunotherapies, for which novel PET tracers are being developed, and discuss what steps are needed to make this vision a reality.
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Affiliation(s)
- Fiona Hegi-Johnson
- Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
| | - Stacey Rudd
- Department of Chemistry, University of Melbourne, Melbourne, VIC, Australia
| | - Rodney J Hicks
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
- Department of Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Dirk De Ruysscher
- Department of Radiation Oncology (Maastro), GROW School for Oncology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Joseph A Trapani
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
- Cancer Immunology Program, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Thomas John
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Paul Donnelly
- Department of Chemistry, University of Melbourne, Melbourne, VIC, Australia
| | - Benjamin Blyth
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
| | - Gerard Hanna
- Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
| | - Sarah Everitt
- Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
| | - Peter Roselt
- Department of Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Michael P MacManus
- Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia.
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11
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Browning Epicardial Adipose Tissue: Friend or Foe? Cells 2022; 11:cells11060991. [PMID: 35326442 PMCID: PMC8947372 DOI: 10.3390/cells11060991] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 02/08/2023] Open
Abstract
The epicardial adipose tissue (EAT) is the visceral fat depot of the heart which is highly plastic and in direct contact with myocardium and coronary arteries. Because of its singular proximity with the myocardium, the adipokines and pro-inflammatory molecules secreted by this tissue may directly affect the metabolism of the heart and coronary arteries. Its accumulation, measured by recent new non-invasive imaging modalities, has been prospectively associated with the onset and progression of coronary artery disease (CAD) and atrial fibrillation in humans. Recent studies have shown that EAT exhibits beige fat-like features, and express uncoupling protein 1 (UCP-1) at both mRNA and protein levels. However, this thermogenic potential could be lost with age, obesity and CAD. Here we provide an overview of the physiological and pathophysiological relevance of EAT and further discuss whether its thermogenic properties may serve as a target for obesity therapeutic management with a specific focus on the role of immune cells in this beiging phenomenon.
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Yang J, Zhang H, Parhat K, Xu H, Li M, Wang X, Ran C. Molecular Imaging of Brown Adipose Tissue Mass. Int J Mol Sci 2021; 22:ijms22179436. [PMID: 34502347 PMCID: PMC8431742 DOI: 10.3390/ijms22179436] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 12/28/2022] Open
Abstract
Brown adipose tissue (BAT), a uniquely thermogenic tissue that plays an important role in metabolism and energy expenditure, has recently become a revived target in the fight against metabolic diseases, such as obesity, diabetes, and non-alcoholic fatty liver disease (NAFLD). Different from white adipose tissue (WAT), the brown adipocytes have distinctive features including multilocular lipid droplets, a large number of mitochondria, and a high expression of uncoupling protein-1 (UCP-1), as well as abundant capillarity. These histologic characteristics provide an opportunity to differentiate BAT from WAT using imaging modalities, such as PET/CT, SPECT/CT, MRI, NIRF and Ultrasound. However, most of the reported imaging methods were BAT activation dependent, and the imaging signals could be affected by many factors, including environmental temperatures and the states of the sympathetic nervous system. Accurate BAT mass detection methods that are independent of temperature and hormone levels have the capacity to track the development and changes of BAT throughout the lifetime of mammals, and such methods could be very useful for the investigation of potential BAT-related therapies. In this review, we focus on molecular imaging modalities that can detect and quantify BAT mass. In addition, their detection mechanism and limitations will be discussed as well.
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Affiliation(s)
- Jing Yang
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, MA 02129, USA
- Correspondence: (J.Y.); (C.R.)
| | - Haili Zhang
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Kadirya Parhat
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Hui Xu
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Mingshuang Li
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Xiangyu Wang
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Chongzhao Ran
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, MA 02129, USA
- Correspondence: (J.Y.); (C.R.)
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Morrissey NA, Beall C, Ellacott KLJ. Absence of the mitochondrial translocator protein 18 kDa in mice does not affect body weight or food intake responses to altered energy availability. J Neuroendocrinol 2021; 33:e13027. [PMID: 34423477 DOI: 10.1111/jne.13027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 07/21/2021] [Accepted: 08/05/2021] [Indexed: 11/29/2022]
Abstract
Changes in mitochondrial function in a variety of cells/tissues are critical for orchestrating systemic energy homeostasis and are linked to the development of obesity and many of its comorbidities. The mitochondrial translocator protein of 18 kDa (TSPO) is expressed in organs throughout the body, including the brain, liver, adipose tissue, gonads and adrenal glands, where it is implicated in regulating steroidogenesis and cellular metabolism. Prior work from our group and others has shown that, in rodents, TSPO levels are altered in adipose tissue by obesity and that modulation of TSPO activity may impact systemic glucose homeostasis. Furthermore, in vitro studies in a variety of cell types have implicated TSPO in mediating cellular energetics and substrate utilisation. Although mice with germline global TSPO deficiency (TSPO-/- ) have no reported changes in body weight under standard husbandry conditions, we hypothesised that, given the roles of TSPO in regulating mitochondrial function and cellular metabolic flexibility, these animals may have alterations in their systemic response to altered energy availability, either nutritional excess or insufficiency. In agreement with published work, compared to wild-type (TSPO+/+ ) littermates, TSPO-/- mice of both sexes did not exhibit differences in body weight on standard chow. Furthermore, following a 12-hour overnight fast, there was no difference in weight loss or compensatory food intake during re-feeding. Five weeks of feeding a high-fat diet (HFD) did not reveal any impact of the absence of TSPO on body weight gain in either male or female mice. Basal blood glucose levels and glucose clearance in a glucose tolerance test were influenced by feeding a HFD diet but not by genotype. In conclusion, in the paradigms examined, germline global deletion of TSPO did not change the physiological response to deviations in systemic energy availability at the whole organism level.
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Affiliation(s)
- Nicole A Morrissey
- Neuroendocrine Research Group, Institute of Biomedical & Clinical Sciences, College of Medicine & Health, University of Exeter, Exeter, UK
| | - Craig Beall
- Neuroendocrine Research Group, Institute of Biomedical & Clinical Sciences, College of Medicine & Health, University of Exeter, Exeter, UK
| | - Kate L J Ellacott
- Neuroendocrine Research Group, Institute of Biomedical & Clinical Sciences, College of Medicine & Health, University of Exeter, Exeter, UK
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Abstract
PURPOSE Cancer immunotherapy has shown huge potential in the fight against cancer, but only a small proportion of patients respond successfully to treatment. Non-invasive methods to stratify responders from non-responders are critically important as immune therapies are often associated with immune-related side effects. Currently, conventional clinical imaging modalities do not provide a useful measure of immune therapy efficacy. Sensitive imaging biomarkers that provide information about the tumoural microenvironment may provide useful insights allowing for improved patient management. PROCEDURES We have assessed the ability of a number of radiopharmaceuticals to non-invasively measure different aspects of the tumour microenvironment and correlated tumour uptake to immune therapy response in a syngeneic model of colon cancer, CT26-WT. Four radiopharmaceuticals, [18F]FDG (a glucose analogue), [18F]FEPPA (a marker for macrophage activation), [18F]FB-IL2 (a marker for CD25+ cells) and [68Ga] Ga-mNOTA-GZP (a marker for granzyme B, the serine protease downstream effector of cytotoxic T cells), were assessed as potential biomarkers to help stratify response to PD-1 monotherapy or combined anti-PD1 and CLTA4 therapy in vivo correlating tumour uptake with changes in tumour-associated immune cell populations. RESULTS [18F]FDG, [18F]FEPPA and [18F]FB-IL2 (a marker for CD25+ cells) showed limited ability to determine therapy response and showed little correlation to tumour-associated immune cell changes. However, [68Ga] Ga-mNOTA-GZP showed good predictive ability and correlated well with changes in tumour-associated T cells, especially CD8+ T cells. CONCLUSIONS [68Ga]Ga-mNOTA-GZP uptake correlates well with changes in CD8+ T cell populations supporting continued development of granzyme B-based imaging agents for stratification of response to immunotherapy. Early assessment of immunotherapy efficacy with [68Ga]Ga-mNOTA-GZP may allow for the reduction of unnecessary side effects while significantly improving patient management.
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Crandall JP, Wahl RL. Perspectives on Brown Adipose Tissue Imaging: Insights from Preclinical and Clinical Observations from the Last and Current Century. J Nucl Med 2021; 62:34S-43S. [PMID: 34230071 DOI: 10.2967/jnumed.120.246991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/22/2020] [Indexed: 11/16/2022] Open
Abstract
Brown adipose tissue (BAT) was first described in the 16th century, but until late last century had mainly been considered a tissue with the function of nonshivering thermogenesis, maintaining body temperature in key organs in newborns who have high body surface areas relative to their weight and thus marked radiative heat loss. BAT was believed to have substantially disappeared by adulthood. Molecular imaging with 18F-FDG PET and PET combined with CT, as well as imaging with 131I-metaiodobenzylguanidine (MIBG) beginning late last century have shown BAT to be present and active well into adulthood. This review highlights key aspects of BAT biology, early empiric observations misidentifying BAT, pitfalls in image interpretation, and methods to intentionally reduce BAT uptake, and outlines multiple imaging methods used to identify BAT in vivo. The therapeutic potential of increasing the amount or activity of BAT for weight loss and improvement of glucose and lipid profiles is highlighted as a major opportunity. Molecular imaging can help dissect the physiology of this complex dynamic tissue and offers the potential for addressing challenges separating "active BAT" from "total BAT." Research in BAT has grown extensively, and 18F-FDG PET is the key imaging procedure against which all other BAT imaging methods must be compared. Given the multiple functions of BAT, it is reasonable to consider it a previously unrecognized endocrine tissue and thus an appropriate topic for review in this supplement to The Journal of Nuclear Medicine.
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Affiliation(s)
- John P Crandall
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Richard L Wahl
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
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Yang F, Zhou N, Zhu X, Min C, Zhou W, Li X. n-3 PUFAs protect against adiposity and fatty liver by promoting browning in postnatally overfed male rats: a role for NRG4. J Nutr Biochem 2021; 93:108628. [PMID: 33705952 DOI: 10.1016/j.jnutbio.2021.108628] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/05/2020] [Accepted: 02/02/2021] [Indexed: 02/06/2023]
Abstract
Early-life nutrition plays an important role in regulating adult metabolism. This study evaluated the effects of early nutrition during the suckling and postweaning periods on expression of the adipocytokine Neuregulin 4 (Nrg4) and its relationship with nonalcoholic fatty liver disease (NAFLD) in adulthood. In vivo, male rats were adjusted to litter sizes of three (small litter, SL) or ten (normal litter, NL) on postnatal day 3. Pups were fed control chow (NL and SL groups) or a high-fat diet (NL-HF and SL-HF groups), and SL pups specifically were fed a fish oil diet rich in n-3 polyunsaturated fatty acids (n-3 PUFAs) (SL-FO group), from postnatal weeks 3 to 13. The results demonstrated that postnatal overnutrition increased weight, hepatic de novo lipogenesis (DNL) gene expression and NAFLD and decreased body temperature and Nrg4, Ucp1 and Pgc1a mRNA expression in adipose tissues in SL, SL-HF and NL-HF rats compared to NL rats in adulthood. The opposite trends were observed in SL-FO rats. Moreover, in vitro, recombinant NRG4 protein reduced lipid accumulation by inhibiting DNL gene expression in fatty HepG2 cells stimulated with sodium oleate. In HPAs, eicosapentaenoic acid (EPA) treatment elevated NRG4 production and caused adipocyte browning, and these effects were abrogated by PPARG antagonism. In conclusion, a postweaning n-3 PUFA diet enhanced Nrg4 expression in adipose tissues, associated with attenuation of NAFLD induced by SL rearing. Additionally, external NRG4 reduced lipogenesis in steatotic hepatocytes. Thus, white adipose tissue browning induced by n-3 PUFAs may promote NRG4 production through the PPARG pathway.
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Affiliation(s)
- Fan Yang
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Nan Zhou
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Xiaolei Zhu
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Cuiting Min
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Wei Zhou
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Xiaonan Li
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China; Institute of Pediatric Research, Nanjing Medical University, Nanjing, Jiangsu Province, China.
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Niu N, Xing H, Wang X, Ding J, Hao Z, Ren C, Ba J, Zheng L, Fu C, Zhao H, Huo L. Comparative [ 18F]FDG and [ 18F]DPA714 PET imaging and time-dependent changes of brown adipose tissue in tumour-bearing mice. Adipocyte 2020; 9:542-549. [PMID: 32902340 PMCID: PMC7714432 DOI: 10.1080/21623945.2020.1814546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Brown adipose tissue (BAT) is important in monitoring energy homeostasis and cancer cachexia. Different from white adipose tissue, BAT is characterized by the presence of a large number of mitochondria in adipocytes. Translocator protein 18 kDa (TSPO), a critical transporter, is expressed in the outer membrane of mitochondria. We speculated that [18F]DPA714, a specific TSPO tracer, may monitor BAT activity in tumor-bearing mice in vivo. We first analyzed the radioactive uptake of positron emission tomography (PET) tracers in BAT of CT26 xenograft mice with 18F-fluorodeoxyglucose ([18F]FDG) and [18F]DPA714. We also studied the BAT uptake of [18F]DPA714 in CT26, A549 and LLC tumor models. The dynamic distribution of [18F]FDG is quite variable among animals, even in mice of the same tumor model (%ID/g-mean: mean ± SDM, 8.61 ± 8.90, n = 16). Contrarily, [18F]DPA714 produced high-quality and stable BAT imaging in different tumor models and different animals of the same model. Interestingly, %ID/g-mean of [18F]DPA714 in BAT was significantly higher on day 26 than that on day 7 in CT26 xenograft model. Taken together, these results strongly indicate the potential feasibility of [18F]DPA714 PET imaging in investigating BAT and energy metabolism during tumor progression in preclinical and clinical study.
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Affiliation(s)
- Na Niu
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Haiqun Xing
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Xuezhu Wang
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Jie Ding
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Zhixin Hao
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Chao Ren
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Jiantao Ba
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Lianfang Zheng
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Chao Fu
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Haiyan Zhao
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Li Huo
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (CAMS & PUMC), Beijing, China
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Oh C, Song IH, Lee W, Jeon M, Choi J, Baek S, Lee BC, Kim SE, Im HJ. Brown adipose tissue imaging using the TSPO tracer [ 18F]fluoromethyl-PBR28-d 2: A comparison with [ 18F]FDG. Nucl Med Biol 2020; 90-91:98-103. [PMID: 33189950 DOI: 10.1016/j.nucmedbio.2020.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 09/02/2020] [Accepted: 10/17/2020] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Currently, the reference method of brown adipose tissue (BAT) imaging is 18F-fluorodeoxyglucose positron emission tomography ([18F]FDG PET). BAT imaging by [18F]FDG PET requires additional stimulation process, which is inconvenient and hard to be standardized. The translocator protein 18 kDa (TSPO) PET has been found to be effective for visualization of BAT. Herein, we evaluated the feasibility of [18F]fluoromethyl-PBR28-d2 ([18F]fmPBR28-d2), a TSPO PET tracer, for interscapular BAT imaging in comparison with [18F]FDG PET. METHODS C57BL/6 mice were used for the [18F]fmPBR28-d2 and [18F]FDG PET imaging. [18F]fmPBR28-d2 PET was performed in the thermoneutral condition (n = 5) and after cold exposure (4 °C for 4 h) on the next day using the same mice. [18F]FDG PET was performed in the thermoneutral and cold exposure conditions with the same method with [18F]fmPBR28-d2 PET. Ex vivo biodistribution study of [18F]fmPBR28-d2 was performed in ten C57BL/6 mice (5: thermoneutral, 5: cold exposure). TSPO immunohistochemistry was done in interscapular BAT. RESULTS The [18F]fmPBR28-d2 PET images showed prominent interscapular BAT uptakes under both thermoneutral and cold exposure conditions. While, the BAT uptake was significantly higher under the cold exposure condition than the thermoneutral condition (12.83 ± 5.06 vs. 22.50 ± 6.03, P = 0.007). Also, [18F]FDG PET imaging showed higher BAT uptake under the cold exposure condition than thermoneutral condition (8.40 ± 0.63 vs. 21.41 ± 4.03, P = 0.001). The interscapular BAT to background (thigh muscle) ratio was higher in [18F]fmPBR28-d2 PET than [18F]FDG PET under both thermoneutral and cold exposure conditions. Ex vivo biodistribution study using [18F]fmPBR28-d2 also showed higher BAT uptake under cold exposure than the thermoneutral condition (8.86 ± 1.74 vs.16.93 ± 4.74, P = 0.036). Also, IHC demonstrated that TSPO expression was significantly increased in the cold exposure group. CONCLUSIONS [18F]FmPBR28-d2 PET demonstrated prominent interscapular BAT uptakes regardless of additional stimulation, and showed a higher BAT to background ratio than [18F]FDG PET. Also, we found that [18F]fmPBR28-d2 PET uptake and TSPO expression of BAT increased under cold exposure condition. Further works are warranted to assess the clinical significance of TSPO PET uptake in BAT.
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Affiliation(s)
- Chiwoo Oh
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - In Ho Song
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Republic of Korea
| | - Wooseung Lee
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - Miyeon Jeon
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - Jinyeong Choi
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - Seungki Baek
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - Byung Chul Lee
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Republic of Korea; Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 16229, Republic of Korea. http://tmtl.snu.ac.kr
| | - Sang Eun Kim
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Republic of Korea; Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 16229, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyung-Jun Im
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea.
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Li W, Ma J, Jiang Q, Zhang T, Qi Q, Cheng Y. Fast Noninvasive Measurement of Brown Adipose Tissue in Living Mice by Near-Infrared Fluorescence and Photoacoustic Imaging. Anal Chem 2020; 92:3787-3794. [PMID: 32066237 DOI: 10.1021/acs.analchem.9b05162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aberrant brown adipose tissue (BAT) metabolism is linked to obesity as well as other metabolic disorders. However, the paucity of imaging tools limits the study of in vivo BAT metabolism in animal models. The current work evaluated a heptamethine dye (CyHF-8) in living mice as a dual-modality BAT-avid molecular probe for two imaging approaches, including near-infrared fluorescence imaging (NIRF) and photoacoustic imaging (PAI). CyHF-8 exhibited favorable spectral properties in the near-infrared window (786/787/805 nm) and accumulated in the subcellular mitochondria of brown adipocytes. After intravenous injection of CyHF-8, NIRF and PAI were both capable of noninvasively detecting interscapular BAT at early time points in living mice. Quantitative analysis of NIRF and PAI images showed that CyHF-8 signals respond to dynamic BAT changes in mice stimulated by norepinephrine (NE) and in diabetic mice induced by streptozotocin (STZ). In summary, dual-modality NIRF/PAI probe CyHF-8 can be used for both NIRF and PAI to noninvasively assess BAT metabolism in living animals.
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Affiliation(s)
- Wanyun Li
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Jing Ma
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Qian Jiang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Ting Zhang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Qingrong Qi
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Yan Cheng
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
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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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