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Peloquin M, Tovar A, Graves JL, Stefanovski D, Tucker K, Marietti E, Greenwood K, Halioua-Haubold CL, Juarez-Salinas D. Saturated fatty acid concentrations are predictive of insulin sensitivity and beta cell compensation in dogs. Sci Rep 2024; 14:12639. [PMID: 38825593 PMCID: PMC11144705 DOI: 10.1038/s41598-024-63373-5] [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: 01/22/2024] [Accepted: 05/28/2024] [Indexed: 06/04/2024] Open
Abstract
Chronic feeding of a high fat diet (HFD) in preclinical species induces broad metabolic dysfunction characterized by body weight gain, hyperinsulinemia, dyslipidemia and impaired insulin sensitivity. The plasma lipidome is not well characterized in dogs with HFD-induced metabolic dysfunction. We therefore aimed to describe the alterations that occur in the plasma lipid composition of dogs that are fed a HFD and examine the association of these changes with the clinical signs of metabolic dysfunction. Dogs were fed a normal diet (ND) or HFD for 12 weeks. Insulin sensitivity (SI) and beta cell compensation (AIRG) were assessed through an intravenous glucose tolerance test (IVGTT) and serum biochemistry was analyzed before the introduction of HFD and again after 12 weeks of continued ND or HFD feeding. Plasma lipidomics were conducted prior to the introduction of HFD and again at week 8 in both ND and HFD-fed dogs. 12 weeks of HFD feeding resulted in impaired insulin sensitivity and increased beta cell compensation measured by SI (ND mean: 11.5 [mU/l]-1 min-1, HFD mean: 4.7 [mU/l]-1 min-1) and AIRG (ND mean: 167.0 [mU/l]min, HFD mean: 260.2 [mU/l]min), respectively, compared to dogs fed ND over the same duration. Chronic HFD feeding increased concentrations of plasma lipid species and deleterious fatty acids compared to dogs fed a ND. Saturated fatty acid (SFA) concentrations were significantly associated with fasting insulin (R2 = 0.29), SI (R2 = 0.49) and AIRG (R2 = 0.37) in all dogs after 12 weeks, irrespective of diet. Our results demonstrate that chronic HFD feeding leads to significant changes in plasma lipid composition and fatty acid concentrations associated with metabolic dysfunction. High SFA concentrations may be predictive of deteriorated insulin sensitivity in dogs.
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Affiliation(s)
| | | | | | - Darko Stefanovski
- Department of Clinical Studies - NBC, University of Pennsylvania School of Veterinary Medicine, Kennett Square, PA, USA
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Ahmad S, Drag MH, Mohamad Salleh S, Cai Z, Nielsen MO. Gene coexpression network analysis reveals perirenal adipose tissue as an important target of prenatal malnutrition in sheep. Physiol Genomics 2023; 55:392-413. [PMID: 37458462 PMCID: PMC10642927 DOI: 10.1152/physiolgenomics.00128.2022] [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: 08/17/2022] [Revised: 06/28/2023] [Accepted: 07/03/2023] [Indexed: 08/24/2023] Open
Abstract
We have previously demonstrated that pre- and early postnatal malnutrition in sheep induced depot- and sex-specific changes in adipose morphological features, metabolic outcomes, and transcriptome in adulthood, with perirenal (PER) as the major target followed by subcutaneous (SUB) adipose tissue. We aimed to identify coexpressed and hub genes in SUB and PER to identify the underlying molecular mechanisms contributing to the early nutritional programming of adipose-related phenotypic outcomes. Transcriptomes of SUB and PER of male and female adult sheep with different pre- and early postnatal nutrition histories were used to construct networks of coexpressed genes likely to be functionally associated with pre- and early postnatal nutrition histories and phenotypic traits using weighted gene coexpression network analysis. The modules from PER showed enrichment of cell cycle regulation, gene expression, transmembrane transport, and metabolic processes associated with both sexes' prenatal nutrition. In SUB (only males), a module of enriched adenosine diphosphate metabolism and development correlated with prenatal nutrition. Sex-specific module enrichments were found in PER, such as chromatin modification in the male network but histone modification and mitochondria- and oxidative phosphorylation-related functions in the female network. These sex-specific modules correlated with prenatal nutrition and adipocyte size distribution patterns. Our results point to PER as a primary target of prenatal malnutrition compared to SUB, which played only a minor role. The prenatal programming of gene expression and cell cycle, potentially through epigenetic modifications, might be underlying mechanisms responsible for observed changes in PER expandability and adipocyte-size distribution patterns in adulthood in both sexes.
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Affiliation(s)
- Sharmila Ahmad
- Department of Animal Science, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Research Unit of Nutrition, Department of Animal and Veterinary Sciences, Aarhus University, Tjele, Denmark
| | - Markus Hodal Drag
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Copenhagen Zoo, Frederiksberg, Denmark
| | - Suraya Mohamad Salleh
- Department of Animal Science, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Zexi Cai
- Centre for Quantitative Genetics and Genomics, Aarhus University, Tjele, Denmark
| | - Mette Olaf Nielsen
- Research Unit of Nutrition, Department of Animal and Veterinary Sciences, Aarhus University, Tjele, Denmark
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Kabir M, Bergman RN, Porter J, Stefanovski D, Paszkiewicz RL, Piccinini F, Woolcott OO, Yang H, Sashi Gopaul V, Stiles L, Kolka CM. Dapagliflozin prevents abdominal visceral and subcutaneous adipose tissue dysfunction in the insulin-resistant canine model. Obesity (Silver Spring) 2023; 31:1798-1811. [PMID: 37221655 PMCID: PMC10981466 DOI: 10.1002/oby.23771] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 05/25/2023]
Abstract
OBJECTIVE Sodium-glucose cotransporter 2 inhibitors (SGLT2i) promote urinary glucose excretion, induce weight loss, and reduce fat accumulation. The effects of the SGLT2i dapagliflozin (DAPA) on subcutaneous (SC) and visceral (VIS) adipose tissue function remain unclear. The objective of this study is to evaluate SC and VIS adipose tissue function in an insulin-resistant canine model. METHODS A total of 12 dogs were fed a high-fat diet (HFD) for 6 weeks and then were given a single low dose of streptozotocin (18.5 mg/kg) to induce insulin resistance. Animals were then randomized and exposed to DAPA (n = 6, 1.25 mg/kg) or placebo (n = 6) once per day for 6 weeks while remaining on the HFD. RESULTS DAPA prevented further weight gain induced by the HFD and normalized fat mass. DAPA reduced fasting glucose and increased free fatty acids, adiponectin, and β-hydroxybutyrate. DAPA reduced adipocyte diameter and cell distribution. Furthermore, DAPA increased genes associated with beiging, lipolysis, and adiponectin secretion and the expression of the adiponectin receptor ADR2, in SC and VIS adipose tissue. DAPA increased AMP-activated protein kinase activity and maximal mitochondrial respiratory function, especially in the SC depot. Furthermore, DAPA reduced cytokines and ceramide synthesis enzymes in SC and VIS depots. CONCLUSIONS For the first time, to our knowledge, we identify mechanisms by which DAPA enhances adipose tissue function in regulating energy homeostasis in an insulin-resistant canine model.
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Affiliation(s)
- Morvarid Kabir
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Richard N Bergman
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Jay Porter
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Darko Stefanovski
- University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA
| | - Rebecca L Paszkiewicz
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Francesca Piccinini
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Orison O. Woolcott
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - HsiuChiung Yang
- Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca Gothenburg, Sweden
| | - V Sashi Gopaul
- Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca Gothenburg, Sweden
| | - Linsey Stiles
- Department of Endocrinology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - Cathryn M Kolka
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
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Metabolic imprinting induced by a high-sugar diet: effects on microRNA expression and insulin resistance in young rats. Mol Biol Rep 2022; 49:8173-8178. [PMID: 35713801 DOI: 10.1007/s11033-022-07473-3] [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: 07/23/2021] [Revised: 02/18/2022] [Accepted: 04/13/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Metabolic imprinting describes associations between nutritional experiences of early life and the development of diseases later in life. The goal of this study was to evaluate the metabolic imprinting induced by a high-sugar diet (HSD) and its effects on microRNA (miRNA) expression and insulin resistance (IR) in young rats. We assessed the effects of expression of adipogenic (miR-200c) and metabolic (miR-126a) miRNAs in retroperitoneal white adipose tissue (rWAT) on IR development. METHODS AND RESULTS Weaned male Wistar rats (N = 6) were fed a standard chow diet or HSD (68% carbohydrates) for 4-, 8-, or 12-weeks. Serum samples were collected to measure triacylglycerol and VLDL-cholesterol, and we assessed glucometabolic parameters (glucose, insulin, HOMA-IR, and QUICKI). rWAT was collected for microRNA analysis (N = 3). The HSD resulted in body fat accretion and IR after 8-weeks, which resolved by 12-weeks. Moreover, the HSD had a time-dependent effect on miRNA relative expression, downregulating rno-miR-200c-3p at week 8 and rno-miR-126a-3p at week 12. CONCLUSIONS MiR-200 family dysregulation has been related to IR, and miR-126a downregulation could be associated with the improvement in IR observed after a 12-week HSD feeding period. This is the first time that excessive sugar intake post-weaning has been associated with miRNA production by rWAT with an impact on IR development.
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de Medeiros SF, Rodgers RJ, Norman RJ. Adipocyte and steroidogenic cell cross-talk in polycystic ovary syndrome. Hum Reprod Update 2021; 27:771-796. [PMID: 33764457 DOI: 10.1093/humupd/dmab004] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 01/08/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Metabolic and endocrine alterations in women with polycystic ovary syndrome (PCOS) affect adipose tissue mass and distribution. PCOS is characterised by hyperandrogenism, obesity and adipocyte dysfunction. Hyperandrogenism in PCOS drives dysfunctional adipocyte secretion of potentially harmful adipocytokines. Glucocorticoids and sex-steroids modulate adipocyte development and function. For their part, adipocyte products interact with adrenal and ovarian steroidogenic cells. Currently, the relationship between adipocyte and steroidogenic cells is not clear, and for these reasons, it is important to elucidate the interrelationship between these cells in women with and without PCOS. OBJECTIVE AND RATIONALE This comprehensive review aims to assess current knowledge regarding the interrelationship between adipocytes and adrenal and ovarian steroidogenic cells in animal models and humans with or without PCOS. SEARCH METHODS We searched for articles published in English and Portuguese in PubMed. Keywords were as follows: polycystic ovary syndrome, steroidogenesis, adrenal glands, theca cells, granulosa cells, adipocytes, adipocytokines, obesity, enzyme activation, and cytochrome P450 enzymes. We expanded the search into the references from the retrieved articles. OUTCOMES Glucocorticoids and sex-steroids modulate adipocyte differentiation and function. Dysfunctional adipocyte products play important roles in the metabolic and endocrine pathways in animals and women with PCOS. Most adipokines participate in the regulation of the hypothalamic-pituitary-adrenal and ovarian axes. In animal models of PCOS, hyperinsulinemia and poor fertility are common; various adipokines modulate ovarian steroidogenesis, depending on the species. Women with PCOS secrete unbalanced levels of adipocyte products, characterised by higher levels of leptin and lower levels of adiponectin. Leptin expression positively correlates with body mass index, waist/hip ratio and levels of total cholesterol, triglyceride, luteinising hormone, oestradiol and androgens. Leptin inhibits the production of oestradiol and, in granulosa cells, may modulate 17-hydroxylase and aromatase enzyme activities. Adiponectin levels negatively correlate with fat mass, body mass index, waist-hip ratio, glucose, insulin and triglycerides, and decrease androgen production by altering expression of luteinising hormone receptor, steroidogenic acute regulatory protein, cholesterol-side-chain cleavage enzyme and 17-hydroxylase. Resistin expression positively correlates with body mass index and testosterone, and promotes the expression of 17-hydroxylase enzyme in theca cells. The potential benefits of adipokines in the treatment of women with PCOS require more investigation. WIDER IMPLICATIONS The current data regarding the relationship between adipocyte products and steroidogenic cells are conflicting in animals and humans. Polycystic ovary syndrome is an excellent model to investigate the interrelationship among adipocyte and steroidogenic cells. Women with PCOS manifest some pathological conditions associated with hyperandrogenism and adipocyte products. In animals, cross-talk between cells may vary according to species, and the current review suggests opportunities to test new medications to prevent or even reverse several harmful sequelae of PCOS in humans. Further studies are required to investigate the possible therapeutic application of adipokines in women with obese and non-obese PCOS. Meanwhile, when appropriate, metformin use alone, or associated with flutamide, may be considered for therapeutic purposes.
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Affiliation(s)
- Sebastião Freitas de Medeiros
- Department of Gynecology and Obstetrics, Medical School, Federal University of Mato Grosso; and Tropical Institute of Reproductive Medicine,Cuiabá, MT, Brazil
| | - Raymond Joseph Rodgers
- Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - Robert John Norman
- Robinson Research Institute Adelaide Medical School, Adelaide, South Australia, Australia
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Paszkiewicz RL, Bergman RN, Santos RS, Frank AP, Woolcott OO, Iyer MS, Stefanovski D, Clegg DJ, Kabir M. A Peripheral CB1R Antagonist Increases Lipolysis, Oxygen Consumption Rate, and Markers of Beiging in 3T3-L1 Adipocytes Similar to RIM, Suggesting that Central Effects Can Be Avoided. Int J Mol Sci 2020; 21:E6639. [PMID: 32927872 PMCID: PMC7554772 DOI: 10.3390/ijms21186639] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 09/03/2020] [Accepted: 09/08/2020] [Indexed: 02/07/2023] Open
Abstract
With the increased prevalence of obesity and related co-morbidities, such as type 2 diabetes (T2D), worldwide, improvements in pharmacological treatments are necessary. The brain- and peripheral-cannabinoid receptor 1 (CB1R) antagonist rimonabant (RIM) has been shown to induce weight loss and improve glucose homeostasis. We have previously demonstrated that RIM promotes adipose tissue beiging and decreased adipocyte cell size, even during maintenance on a high-fat diet. Given the adverse side-effects of brain-penetrance with RIM, in this study we aimed to determine the site of action for a non-brain-penetrating CB1R antagonist AM6545. By using in vitro assays, we demonstrated the direct effects of this non-brain-penetrating CB1R antagonist on cultured adipocytes. Specifically, we showed, for the first time, that AM6545 significantly increases markers of adipose tissue beiging, mitochondrial biogenesis, and lipolysis in 3T3-L1 adipocytes. In addition, the oxygen consumption rate (OCR), consisting of baseline respiratory rate, proton leak, maximal respiratory capacity, and ATP synthase activity, was greater for cells exposed to AM6545, demonstrating greater mitochondrial uncoupling. Using a lipolysis inhibitor during real-time OCR measurements, we determined that the impact of CB1R antagonism on adipocytes is driven by increased lipolysis. Thus, our data suggest the direct role of CB1R antagonism on adipocytes does not require brain penetrance, supporting the importance of focus on peripheral CB1R antagonism pharmacology for reducing the incidence of obesity and T2D.
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Affiliation(s)
- Rebecca L. Paszkiewicz
- Sports Spectacular Diabetes and Obesity Wellness and Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; (R.L.P.); (R.N.B.); (R.S.S.); (A.P.F.); (O.O.W.); (M.S.I.)
| | - Richard N. Bergman
- Sports Spectacular Diabetes and Obesity Wellness and Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; (R.L.P.); (R.N.B.); (R.S.S.); (A.P.F.); (O.O.W.); (M.S.I.)
| | - Roberta S. Santos
- Sports Spectacular Diabetes and Obesity Wellness and Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; (R.L.P.); (R.N.B.); (R.S.S.); (A.P.F.); (O.O.W.); (M.S.I.)
| | - Aaron P. Frank
- Sports Spectacular Diabetes and Obesity Wellness and Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; (R.L.P.); (R.N.B.); (R.S.S.); (A.P.F.); (O.O.W.); (M.S.I.)
| | - Orison O. Woolcott
- Sports Spectacular Diabetes and Obesity Wellness and Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; (R.L.P.); (R.N.B.); (R.S.S.); (A.P.F.); (O.O.W.); (M.S.I.)
| | - Malini S. Iyer
- Sports Spectacular Diabetes and Obesity Wellness and Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; (R.L.P.); (R.N.B.); (R.S.S.); (A.P.F.); (O.O.W.); (M.S.I.)
| | - Darko Stefanovski
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Deborah J. Clegg
- The College of Nursing and Health Professions, Drexel University, Philadelphia, PA 19104, USA;
| | - Morvarid Kabir
- Sports Spectacular Diabetes and Obesity Wellness and Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; (R.L.P.); (R.N.B.); (R.S.S.); (A.P.F.); (O.O.W.); (M.S.I.)
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7
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Reynolds A, Keen JA, Fordham T, Morgan RA. Adipose tissue dysfunction in obese horses with equine metabolic syndrome. Equine Vet J 2019; 51:760-766. [PMID: 30866087 PMCID: PMC6850304 DOI: 10.1111/evj.13097] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 03/02/2019] [Indexed: 01/05/2023]
Abstract
BACKGROUND Obesity is a common feature of equine metabolic syndrome (EMS). In other species, obese adipose tissue shows pathological features such as adipocyte hypertrophy, fibrosis, inflammation and impaired insulin signalling all of which contribute to whole body insulin dysregulation. Such adipose tissue dysfunction has not been investigated in horses. OBJECTIVES To determine if obese horses with EMS have adipose tissue dysfunction characterised by adipocyte hypertrophy, fibrosis, inflammation and altered insulin signalling. STUDY DESIGN Cross-sectional post-mortem study. METHODS Samples of peri-renal (visceral) and retroperitoneal adipose tissue were obtained at post-mortem from healthy horses (n = 9) and horses with EMS (n = 6). Samples were analysed to determine average adipocyte size, fibrotic content and expression of inflammatory and insulin signalling genes. RESULTS Horses with metabolic syndrome showed marked adipocyte hypertrophy and increased expression of adipokines (leptin) and inflammatory cytokines (TNFα, IL1β and CCL2) in both adipose tissue depots compared to healthy horses. There were no differences in fibrosis or expression of genes relating to insulin signalling between the groups. MAIN LIMITATIONS Cases used in this study had advanced EMS and may represent the end stage of the condition; the design of the study is such that we were unable to relate the identified adipose tissue dysfunction to whole body insulin dysregulation. CONCLUSIONS Horses with obesity and EMS have significant dysfunction of the peri-renal and retroperitoneal adipose tissue that may contribute to whole body insulin dysregulation.
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Affiliation(s)
- A. Reynolds
- Royal (Dick) School of Veterinary StudiesUniversity of EdinburghRoslinMidlothianUK
| | - J. A. Keen
- Royal (Dick) School of Veterinary StudiesUniversity of EdinburghRoslinMidlothianUK
| | - T. Fordham
- Royal (Dick) School of Veterinary StudiesUniversity of EdinburghRoslinMidlothianUK
| | - R. A. Morgan
- Royal (Dick) School of Veterinary StudiesUniversity of EdinburghRoslinMidlothianUK
- University/BHF Centre for Cardiovascular Sciencethe Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK
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8
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Iyer MS, Paszkiewicz RL, Bergman RN, Richey JM, Woolcott OO, Asare-Bediako I, Wu Q, Kim SP, Stefanovski D, Kolka CM, Clegg DJ, Kabir M. Activation of NPRs and UCP1-independent pathway following CB1R antagonist treatment is associated with adipose tissue beiging in fat-fed male dogs. Am J Physiol Endocrinol Metab 2019; 317:E535-E547. [PMID: 31237449 PMCID: PMC6766608 DOI: 10.1152/ajpendo.00539.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 06/21/2019] [Accepted: 06/24/2019] [Indexed: 11/22/2022]
Abstract
CB1 receptor (CB1R) antagonism improves the deleterious effects of a high-fat diet (HFD) by reducing body fat mass and adipocyte cell size. Previous studies demonstrated that the beneficial effects of the CB1R antagonist rimonabant (RIM) in white adipose tissue (WAT) are partially due to an increase of mitochondria numbers and upregulation thermogenesis markers, suggesting an induction of WAT beiging. However, the molecular mechanism by which CB1R antagonism induces weight loss and WAT beiging is unclear. In this study, we probed for genes associated with beiging and explored longitudinal molecular mechanisms by which the beiging process occurs. HFD dogs received either RIM (HFD+RIM) or placebo (PL) (HFD+PL) for 16 wk. Several genes involved in beiging were increased in HFD+RIM compared with pre-fat, HFD, and HFD+PL. We evaluated lipolysis and its regulators including natriuretic peptide (NP) and its receptors (NPRs), β-1 and β-3 adrenergic receptor (β1R, β3R) genes. These genes were increased in WAT depots, accompanied by an increase in lipolysis in HFD+RIM. In addition, RIM decreased markers of inflammation and increased adiponectin receptors in WAT. We observed a small but significant increase in UCP1; therefore, we evaluated the newly discovered UCP1-independent thermogenesis pathway. We confirmed that SERCA2b and RYR2, the two key genes involved in this pathway, were upregulated in the WAT. Our data suggest that the upregulation of NPRs, β-1R and β-3R, lipolysis, and SERCA2b and RYR2 may be one of the mechanisms by which RIM promotes beiging and overall the improvement of metabolic homeostasis induced by RIM.
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MESH Headings
- Adipose Tissue/drug effects
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, White/drug effects
- Animals
- Diet, High-Fat/adverse effects
- Dogs
- Gene Expression/drug effects
- Inflammation/pathology
- Inflammation/prevention & control
- Insulin Resistance
- Male
- Organelle Biogenesis
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Receptors, Atrial Natriuretic Factor/drug effects
- Rimonabant/pharmacology
- Thermogenesis/drug effects
- Thermogenesis/genetics
- Uncoupling Protein 1/drug effects
- Weight Loss/drug effects
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Affiliation(s)
- Malini S Iyer
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | | | - Richard N Bergman
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Joyce M Richey
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Orison O Woolcott
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Isaac Asare-Bediako
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Qiang Wu
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Stella P Kim
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Darko Stefanovski
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Cathryn M Kolka
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Deborah J Clegg
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Morvarid Kabir
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
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9
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Abstract
Adipose morphology is defined as the number and size distribution of adipocytes (fat cells) within adipose tissue. Adipose tissue with fewer but larger adipocytes is said to have a 'hypertrophic' morphology, whereas adipose with many adipocytes of a smaller size is said to have a 'hyperplastic' morphology. Hypertrophic adipose morphology is positively associated with insulin resistance, diabetes and cardiovascular disease. By contrast, hyperplastic morphology is associated with improved metabolic parameters. These phenotypic associations suggest that adipose morphology influences risk of cardiometabolic disease. Intriguingly, monozygotic twin studies have determined that adipose morphology is in part determined genetically. Therefore, identifying the genetic regulation of adipose morphology may help us to predict, prevent and ameliorate insulin resistance and associated metabolic diseases. Here, we review the current literature regarding adipose morphology in relation to: (1) metabolic and medical implications; (2) the methods used to assess adipose morphology; and (3) transcriptional differences between morphologies. We further highlight three mechanisms that have been hypothesized to promote adipocyte hypertrophy and thus to regulate adipose morphology.
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Affiliation(s)
- Panna Tandon
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, UK
| | - Rebecca Wafer
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, UK
| | - James E N Minchin
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, UK
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10
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Richey JM, Woolcott O. Re-visiting the Endocannabinoid System and Its Therapeutic Potential in Obesity and Associated Diseases. Curr Diab Rep 2017; 17:99. [PMID: 28913816 DOI: 10.1007/s11892-017-0924-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE OF REVIEW The purpose of the review was to revisit the possibility of the endocannabinoid system being a therapeutic target for the treatment of obesity by focusing on the peripheral roles in regulating appetite and energy metabolism. RECENT FINDINGS Previous studies with the global cannabinoid receptor blocker rimonabant, which has both central and peripheral properties, showed that this drug has beneficial effects on cardiometabolic function but severe adverse psychiatric side effects. Consequently, focus has shifted to peripherally restricted cannabinoid 1 (CB1) receptor blockers as possible therapeutic agents that mitigate or eliminate the untoward effects in the central nervous system. Targeting the endocannabinoid system using novel peripheral CB1 receptor blockers with negligible penetrance across the blood-brain barrier may prove to be effective therapy for obesity and its co-morbidities. Perhaps the future of blockers targeting CB1 receptors will be tissue-specific neutral antagonists (e.g., skeletal muscle specific to treat peripheral insulin resistance, adipocyte-specific to treat fat excess, liver-specific to treat fatty liver and hepatic insulin resistance).
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Affiliation(s)
- Joyce M Richey
- USC Diabetes and Obesity Research Institute, Keck School of Medicine of USC, 2250 Alcazar Street, Suite 213, Los Angeles, CA, 90089, USA.
| | - Orison Woolcott
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Thalians E103, Los Angeles, CA, 90048, USA
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Bredella MA, Karastergiou K, Bos SA, Gerweck AV, Torriani M, Fried SK, Miller KK. GH administration decreases subcutaneous abdominal adipocyte size in men with abdominal obesity. Growth Horm IGF Res 2017; 35:17-20. [PMID: 28628810 PMCID: PMC5585040 DOI: 10.1016/j.ghir.2017.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 06/06/2017] [Accepted: 06/11/2017] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To investigate the effects of short-term GH administration on abdominal subcutaneous adipocyte size and CT attenuation in men with abdominal obesity. DESIGN 6-week, randomized, double-blind, placebo-controlled study of GH (starting dose 2μg/kg/d) vs placebo of 15 abdominally obese men (mean age: 34±6years; mean BMI: 37.7±6.1kg/m2, mean IGF-1 SDS: -1.9±0.5) who underwent abdominal subcutaneous adipose tissue (SAT) aspirations to determine adipocyte size, CTs for body composition and measures of glucose tolerance at baseline and 6weeks. GH dosing was titrated to target IGF-1 levels in the upper normal age-appropriate range. RESULTS GH administration decreased subcutaneous abdominal adipocyte size compared to placebo. Adipocyte size was positively associated with 120-min glucose and HOMA-IR and inversely associated with peak-stimulated GH and CT attenuation. CT attenuation of SAT was inversely associated with 120-min glucose and HOMA-IR and increased following GH administration. CONCLUSION In men with abdominal obesity, subcutaneous abdominal adipocyte size is positively associated with measures of impaired glucose tolerance and administration of GH at doses that raise IGF-1 levels within the normal range, decreases abdominal subcutaneous adipocyte size, suggesting that GH administration improves the health of adipose tissue. Clinical trials number: NCT00131378.
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Affiliation(s)
- Miriam A Bredella
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.
| | - Kalypso Karastergiou
- Department of Medicine, Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, 650 Albany St., EBRC 810, Boston, MA 02118, United States
| | - Stijn A Bos
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Anu V Gerweck
- Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Martin Torriani
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Susan K Fried
- Department of Medicine, Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, 650 Albany St., EBRC 810, Boston, MA 02118, United States
| | - Karen K Miller
- Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
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12
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Ji B, Qu H, Wang H, Wei H, Deng H. Association Between the Visceral Adiposity Index and Homeostatic Model Assessment of Insulin Resistance in Participants With Normal Waist Circumference. Angiology 2016; 68:716-721. [PMID: 28743220 DOI: 10.1177/0003319716682120] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We assessed the correlation between the visceral adiposity index (VAI; a useful indicator of adipose distribution and function) and homeostatic model assessment of insulin resistance (HOMA-IR) in participants with normal waist circumference. A cross-sectional study was conducted, which included 1834 Chinese adults. The blood pressure, anthropometric measurements, fasting and postprandial blood glucose, fasting insulin, and lipid profiles were measured. The VAI and HOMA-IR were calculated. Participants were divided into 4 groups according to the HOMA-IR level, and the correlation between the VAI and HOMA-IR was analyzed. The VAI gradually increased across the HOMA-IR quartiles ( P < .05), and a Pearson correlation analysis showed that VAI was positively related to the HOMA-IR ( P < .001) in males and females. After adjusting for the other covariates, VAI was independently correlated with the HOMA-IR. A logistic regression analysis indicated that VAI elevation was the main risk factor for the increased HOMA-IR in both genders. Overall, the VAI was closely correlated with the HOMA-IR in a population without central obesity.
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Affiliation(s)
- Baolan Ji
- 1 Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hua Qu
- 1 Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hang Wang
- 1 Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Huili Wei
- 1 Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Huacong Deng
- 1 Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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13
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Docimo S, Lee Y, Chatani P, Rogers AM, Lacqua F. Visceral to subcutaneous fat ratio predicts acuity of diverticulitis. Surg Endosc 2016; 31:2808-2812. [PMID: 27778168 DOI: 10.1007/s00464-016-5290-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 10/13/2016] [Indexed: 12/17/2022]
Abstract
INTRODUCTION There is an association between obesity and more complicated diverticular disease. We hypothesize that this link may be due to an increased level of visceral fat rather than an elevated body mass index alone. Adipose tissue secretes inflammatory cytokines, and chronic inflammation may account for the link between obesity and a more severe presentation of diverticular disease. We have applied a quantitative measure of visceral fat content in a series of patients admitted with diverticulitis, comparing those who required emergent versus elective surgical procedures for diverticulitis. METHODS We performed a retrospective review of all adult patients who underwent emergent or elective surgery at our institution for diverticulitis from 2010 to 2014. Data were collected on demographics, comorbidities, operative findings, complications, and length of stay. Radiologic measurements of adiposity were obtained from preoperative CT scans. Visceral fat areas and subcutaneous fat areas were measured, and the V/S ratio was calculated. RESULTS Thirty-four patients underwent emergent and 32 patients underwent elective surgery. The mean age was 66.3 years for the emergent and 57.11 for the elective group (p = 0.04178). The perinephric, visceral, subcutaneous fat, and V/S ratio for the emergent group were 1.71, 185.22, 338.22, and 0.56 and were 1.11, 127.18, 295.28, and 0.46 for the elective group. The difference between the V/S ratio for each group was significant (p = 0.0238). The emergent group had an average LOS of 16.11 days compared to 5.15 for the elective group (p = <0.00001). The complication rate was significantly higher (p = 0.024) in the emergent group (n = 12, 35.2 %) compared to the elective group (n = 4, 12.5 %). CONCLUSION Our study demonstrates a clinically significant link between visceral fat and severity of presentation of diverticulitis. Patients with higher V/S fat ratios were more likely to require emergency surgery and have more complications and a longer LOS.
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Affiliation(s)
- Salvatore Docimo
- Division of Bariatric, Foregut, and Advanced Gastrointestinal Surgery, Department of Surgery, Stony Brook Medicine, Stony Brook, NY, USA.
| | - Young Lee
- Department of Surgery, NYU Lutheran Medical Center, Brooklyn, NY, USA
| | - Prav Chatani
- Department of Surgery, NYU Lutheran Medical Center, Brooklyn, NY, USA
| | - Ann M Rogers
- Division of Minimally Invasive and Bariatric Surgery, Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA
| | - Frank Lacqua
- Department of Surgery, NYU Lutheran Medical Center, Brooklyn, NY, USA
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14
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Abstract
The domestication and urbanization of dogs and cats has dramatically altered their environment and behavior. Human and pet obesity is a global concern, particularly in developed countries. An increased incidence of chronic disease is associated with obesity secondary to low-grade systemic inflammation. This article reviews current research into the genetic, dietary, and physiologic factors associated with obesity, along with use of "omics" technology to better understand and characterize this disease.
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Affiliation(s)
- Beth Hamper
- Hamper Veterinary Nutritional Consulting, 9160 Crestview Drive, Indianapolis, IN 46240, USA.
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15
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Akhlaghi M. Non-alcoholic Fatty Liver Disease: Beneficial Effects of Flavonoids. Phytother Res 2016; 30:1559-1571. [DOI: 10.1002/ptr.5667] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 05/23/2016] [Accepted: 05/24/2016] [Indexed: 12/31/2022]
Affiliation(s)
- Masoumeh Akhlaghi
- Nutrition Research Center, School of Nutrition and Food Sciences; Shiraz University of Medical Sciences; Shiraz Iran
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16
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Shah RV, Allison MA, Lima JAC, Abbasi SA, Eisman A, Lai C, Jerosch-Herold M, Budoff M, Murthy VL. Abdominal fat radiodensity, quantity and cardiometabolic risk: The Multi-Ethnic Study of Atherosclerosis. Nutr Metab Cardiovasc Dis 2016; 26:114-122. [PMID: 26817938 PMCID: PMC4775418 DOI: 10.1016/j.numecd.2015.12.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 10/29/2015] [Accepted: 12/03/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Fat radiodensity, as measured by fat attenuation on computed tomography (CT), has emerged as a potential biomarker of "fat quality." We sought to characterize the relationship between fat radiodensity and quantity in subcutaneous, visceral, and intermuscular fat depots, and its role in inflammation, insulin resistance, and metabolic syndrome (MetS). METHODS AND RESULTS We studied 1511 individuals from the Multi-Ethnic Study of Atherosclerosis who underwent CT for measurement of regional fat distribution and radiodensity, along with biomarker assessments and adjudication of incident metabolic syndrome (MetS). Linear, logistic and Cox regression analyses were used to measure association between fat radiodensity and (1) fat quantity, (2) biomarkers of cardiometabolic dysfunction, and (3) both prevalent and incident MetS. In each fat depot, radiodensity was strongly and inversely associated with quantity (e.g., visceral fat radiodensity vs. quantity: ρ = -0.82, P < 0.01). After adjustment for age, sex and race, lower visceral fat radiodensity was associated with greater C-reactive protein, leptin and insulin, but lower adiponectin (P < 0.01 for all). After full adjustment for cardiovascular disease risk factors, visceral (but not subcutaneous or intermuscular) fat radiodensity was associated with prevalent MetS (OR = 0.96, 95% CI = 0.93-0.99, P = 0.01). Moreover, lower visceral fat radiodensity was associated with incident MetS after the same adjustment (HR = 0.95, 95% CI 0.93-0.98, P < 0.01). However, this association became non-significant after further adjustment for visceral fat quantity. CONCLUSION Fat radiodensity is strongly correlated with fat quantity and relevant inflammatory biomarkers. Fat radiodensity (especially for visceral fat) may be a complementary, easily assessed marker of cardiometabolic risk.
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Affiliation(s)
- Ravi V Shah
- Department of Medicine, Cardiovascular Division, Beth Israel Deaconess Medical Center, Boston, MA, USA.
| | - M A Allison
- Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA, USA
| | - J A C Lima
- Department of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - S A Abbasi
- Department of Cardiology, Brown University, Providence, RI, USA
| | - A Eisman
- Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - C Lai
- Department of Medicine, Cardiovascular Division, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - M Jerosch-Herold
- Noninvasive Cardiovascular Imaging Section, Cardiovascular Division, Department of Medicine and Department of Radiology, Brigham and Women's Hospital, Boston, MA, USA
| | - M Budoff
- Department of Cardiology and Medicine, University of California-Los Angeles, Los Angeles, CA, USA
| | - V L Murthy
- Department of Medicine (Cardiovascular Medicine Division) and Department of Radiology (Nuclear Medicine Division), University of Michigan, Ann Arbor, MI, USA.
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17
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Broussard JL, Nelson MD, Kolka CM, Bediako IA, Paszkiewicz RL, Smith L, Szczepaniak EW, Stefanovski D, Szczepaniak LS, Bergman RN. Rapid development of cardiac dysfunction in a canine model of insulin resistance and moderate obesity. Diabetologia 2016; 59:197-207. [PMID: 26376797 PMCID: PMC5310691 DOI: 10.1007/s00125-015-3767-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 08/26/2015] [Indexed: 12/30/2022]
Abstract
AIMS/HYPOTHESIS The worldwide incidence of obesity and diabetes continues to rise at an alarming rate. A major cause of the morbidity and mortality associated with obesity and diabetes is heart disease, yet the mechanisms that lead to cardiovascular complications remain unclear. METHODS We performed cardiac MRI to assess left ventricular morphology and function during the development of moderate obesity and insulin resistance in a well-established canine model (n = 26). To assess the influence of dietary fat composition, we randomised animals to a traditional lard diet (rich in saturated and monounsaturated fat; n = 12), a salmon oil diet (rich in polyunsaturated fat; n = 8) or a control diet (n = 6). RESULTS High-fat feeding with lard increased body weight and fasting insulin and markedly reduced insulin sensitivity. Lard feeding also significantly reduced left ventricular function, evidenced by a worsening of circumferential strain and impairment in left ventricular torsion. High-fat feeding with salmon oil increased body weight; however, salmon oil feeding did not impair insulin sensitivity or cardiac function. CONCLUSIONS/INTERPRETATION These data emphasise the importance of dietary fat composition on both metabolic and cardiac function, and have important implications for the relationship between diet and health.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Michael D Nelson
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Laura Smith
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Edward W Szczepaniak
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Darko Stefanovski
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Lidia S Szczepaniak
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.
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18
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Castro AV, Woolcott OO, Iyer MS, Kabir M, Ionut V, Stefanovski D, Kolka CM, Szczepaniak LS, Szczepaniak EW, Asare-Bediako I, Paszkiewicz RL, Broussard JL, Kim SP, Kirkman EL, Rios HC, Mkrtchyan H, Wu Q, Ader M, Bergman RN. Increase in visceral fat per se does not induce insulin resistance in the canine model. Obesity (Silver Spring) 2015; 23:105-11. [PMID: 25322680 PMCID: PMC4276477 DOI: 10.1002/oby.20906] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/30/2014] [Indexed: 12/25/2022]
Abstract
OBJECTIVES To determine whether a selective increase of visceral adipose tissue content will result in insulin resistance. METHODS Sympathetic denervation of the omental fat was performed under general inhalant anesthesia by injecting 6-hydroxydopamine in the omental fat of lean mongrel dogs (n = 11). In the conscious animal, whole-body insulin sensitivity was assessed by the minimal model (SI ) and the euglycemic hyperinsulinemic clamp (SICLAMP ). Changes in abdominal fat were monitored by magnetic resonance. All assessments were determined before (Wk0) and 2 weeks (Wk2) after denervation. Data are medians (upper and lower interquartile). RESULTS Denervation of omental fat resulted in increased percentage (and content) of visceral fat [Wk0: 10.2% (8.5-11.4); Wk2: 12.4% (10.4-13.6); P < 0.01]. Abdominal subcutaneous fat remained unchanged. However, no changes were found in SI [Wk0: 4.7 (mU/l)(-1) min(-1) (3.1-8.8); Wk2: 5.3 (mU/l)(-1) min(-1) (4.5-7.2); P = 0.59] or SICLAMP [Wk0: 42.0 × 10(-4) dl kg(-1) min(-1) (mU/l)(-1) (41.0-51.0); Wk2: 40.0 × 10(-4) dl kg(-1) min(-1) (mU/l) (-1) (34.0-52.0); P = 0.67]. CONCLUSIONS Despite a selective increase in visceral adiposity in dogs, insulin sensitivity in vivo did not change, which argues against the concept that accumulation of visceral adipose tissue contributes to insulin resistance.
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Affiliation(s)
- Ana V.B. Castro
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Orison O. Woolcott
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Malini S. Iyer
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Morvarid Kabir
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Viorica Ionut
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Darko Stefanovski
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Cathryn M. Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Lidia S. Szczepaniak
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Edward W. Szczepaniak
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Isaac Asare-Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | | | - Josiane L. Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Stella P. Kim
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Erlinda L. Kirkman
- Department of Animal Resources, University of Southern California, Los Angeles
| | - Hernan C. Rios
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Hasmik Mkrtchyan
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Qiang Wu
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Marilyn Ader
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Richard N. Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
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19
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Kim SM, Lun M, Wang M, Senyo SE, Guillermier C, Patwari P, Steinhauser ML. Loss of white adipose hyperplastic potential is associated with enhanced susceptibility to insulin resistance. Cell Metab 2014; 20:1049-58. [PMID: 25456741 PMCID: PMC4715375 DOI: 10.1016/j.cmet.2014.10.010] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 09/10/2014] [Accepted: 10/15/2014] [Indexed: 10/24/2022]
Abstract
Fat mass expansion occurs by adipocyte hypertrophy or recruitment of differentiating adipocyte progenitors, the relative balance of which may impact systemic metabolism. We measured adipogenesis in murine subcutaneous (sWAT) and visceral white adipose tissue (vWAT) using stable isotope methodology and then modeled adipocyte turnover. Birth and death rates were similar within depots; however, turnover was higher in vWAT relative to sWAT. In juvenile mice, obesity increased adipogenesis, but in adults, this was only seen in vWAT after prolonged high-fat feeding. Statistical modeling suggests differentiation of adipocyte progenitors without an accompanying self-renewing division step may partially explain the age-dependent decline in hyperplastic potential. Additional metabolic interrogation of obese mice demonstrated an association between adipocyte turnover and insulin sensitivity. These data therefore identify adipocyte hypertrophy as the dominant mechanism of adult fat mass expansion and support the paradoxical concept that metabolic disease ensues due to a failure of adipose tissue plasticity.
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Affiliation(s)
- Soo M Kim
- Department of Medicine, Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Mingyue Lun
- Department of Medicine, Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Mei Wang
- National Resource for Imaging Mass Spectroscopy, Brigham and Women's Hospital, Cambridge, MA 02138, USA
| | - Samuel E Senyo
- Department of Medicine, Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Christelle Guillermier
- Department of Medicine, Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA; National Resource for Imaging Mass Spectroscopy, Brigham and Women's Hospital, Cambridge, MA 02138, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Parth Patwari
- Department of Medicine, Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Matthew L Steinhauser
- Department of Medicine, Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA.
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20
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Shah RV, Murthy VL, Abbasi SA, Blankstein R, Kwong RY, Goldfine AB, Jerosch-Herold M, Lima JAC, Ding J, Allison MA. Visceral adiposity and the risk of metabolic syndrome across body mass index: the MESA Study. JACC Cardiovasc Imaging 2014; 7:1221-35. [PMID: 25440591 PMCID: PMC4268163 DOI: 10.1016/j.jcmg.2014.07.017] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/21/2014] [Accepted: 07/24/2014] [Indexed: 12/21/2022]
Abstract
OBJECTIVES This study sought to evaluate differential effects of visceral fat (VF) and subcutaneous fat and their effects on metabolic syndrome (MetS) risk across body mass index (BMI) categories. BACKGROUND The regional distribution of adipose tissue is an emerging risk factor for cardiometabolic disease, although serial changes in fat distribution have not been extensively investigated. VF and its alterations over time may be a better marker for risk than BMI in normal weight and overweight or obese individuals. METHODS We studied 1,511 individuals in the MESA (Multi-Ethnic Study of Atherosclerosis) with adiposity assessment by computed tomography (CT). A total of 253 participants without MetS at initial scan underwent repeat CT (median interval 3.3 years). We used discrete Cox regression with net reclassification to investigate whether baseline and changes in VF area are associated with MetS. RESULTS Higher VF was associated with cardiometabolic risk and coronary artery calcification, regardless of BMI. After adjustment, VF was more strongly associated with incident MetS than subcutaneous fat regardless of weight, with a 28% greater MetS hazard per 100 cm(2)/m VF area and significant net reclassification (net reclassification index: 0.44, 95% confidence interval [CI]: 0.29 to 0.60) over clinical risk. In individuals with serial imaging, initial VF (hazard ratio: 1.24 per 100 cm(2)/m, 95% CI: 1.08 to 1.44 per 100 cm(2)/m, p = 0.003) and change in VF (hazard ratio: 1.05 per 5% change, 95% CI: 1.01 to 1.08 per 5% change, p = 0.02) were associated with MetS after adjustment. Changes in subcutaneous fat were not associated with incident MetS after adjustment for clinical risk and VF area. CONCLUSIONS VF is modestly associated with BMI. However, across BMI, a single measure of and longitudinal change in VF predict MetS, even accounting for weight changes. Visceral adiposity is essential to assessing cardiometabolic risk, regardless of age, race, or BMI, and may serve as a marker and target of therapy in cardiometabolic disease.
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Affiliation(s)
- Ravi V Shah
- Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Venkatesh L Murthy
- Department of Medicine (Cardiovascular Medicine Division) and Department of Radiology (Nuclear Medicine and Cardiothoracic Imaging Divisions), University of Michigan, Ann Arbor, Michigan.
| | - Siddique A Abbasi
- Non-Invasive Cardiovascular Imaging, Brigham and Women's Hospital, Boston, Massachusetts
| | - Ron Blankstein
- Non-Invasive Cardiovascular Imaging, Brigham and Women's Hospital, Boston, Massachusetts
| | - Raymond Y Kwong
- Non-Invasive Cardiovascular Imaging, Brigham and Women's Hospital, Boston, Massachusetts
| | | | - Michael Jerosch-Herold
- Non-Invasive Cardiovascular Imaging, Brigham and Women's Hospital, Boston, Massachusetts
| | - João A C Lima
- Division of Cardiology, Johns Hopkins Medical Institute, Baltimore, Maryland
| | - Jingzhong Ding
- Department of Medicine, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Matthew A Allison
- Department of Family and Preventative Medicine, University of California-San Diego, San Diego, California
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22
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Müller L, Kollár E, Balogh L, Pöstényi Z, Márián T, Garai I, Balkay L, Trencsényi G, Thuróczy J. Body fat distribution and metabolic consequences - Examination opportunities in dogs. Acta Vet Hung 2014; 62:169-79. [PMID: 24334077 DOI: 10.1556/avet.2013.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The relationship between metabolic disorders and the distribution of fat in different body regions is not clearly understood in humans. The aim of this study was to develop a suitable method for assessing the regional distribution of fat deposits and their metabolic effects in dogs. Twenty-five dogs were subjected to computed tomographic (CT) imaging and blood sampling in order to characterise their metabolic status. The different fat areas were measured on a cross-sectional scan, and the animals' metabolic status was evaluated by measuring fasting glucose, insulin and leptin levels. The volume of visceral adipose tissue is the main determinant of leptin levels. The correlation of visceral fat volume and leptin concentration was found to be independent of insulin levels or the degree of insulin resistance. There was a positive correlation between the visceral to subcutaneous fat volume ratio and serum insulin concentration, and a similar trend was observed in the relationship of fat ratio and insulin resistance. The distribution of body fat essentially influences the metabolic parameters in dogs, but the effects of adiposity differ between humans and dogs. The findings can facilitate a possible extrapolation of results from animal studies to humans with regard to the metabolic consequences of different obesity types.
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Affiliation(s)
- Linda Müller
- 1 Szent István University Department and Clinic of Obstetrics and Animal Reproduction, Faculty of Veterinary Science István u. 2 Budapest H-1078 Hungary
| | - Eszter Kollár
- 1 Szent István University Department and Clinic of Obstetrics and Animal Reproduction, Faculty of Veterinary Science István u. 2 Budapest H-1078 Hungary
| | - Lajos Balogh
- 2 National Frédéric Joliot-Curie Institute of Radiobiology and Radiohygiene Budapest Hungary
| | - Zita Pöstényi
- 2 National Frédéric Joliot-Curie Institute of Radiobiology and Radiohygiene Budapest Hungary
| | - Teréz Márián
- 3 University of Debrecen Department of Nuclear Medicine, Faculty of Medicine Debrecen Hungary
| | - Ildikó Garai
- 3 University of Debrecen Department of Nuclear Medicine, Faculty of Medicine Debrecen Hungary
| | - László Balkay
- 3 University of Debrecen Department of Nuclear Medicine, Faculty of Medicine Debrecen Hungary
| | - György Trencsényi
- 3 University of Debrecen Department of Nuclear Medicine, Faculty of Medicine Debrecen Hungary
| | - Julianna Thuróczy
- 1 Szent István University Department and Clinic of Obstetrics and Animal Reproduction, Faculty of Veterinary Science István u. 2 Budapest H-1078 Hungary
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23
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Sato T, Yasuzawa T, Uesaka A, Izumi Y, Kamiya A, Tsuchiya K, Kobayashi Y, Kuwahata M, Kido Y. Type 2 diabetic conditions in Otsuka Long-Evans Tokushima Fatty rats are ameliorated by 5-aminolevulinic acid. Nutr Res 2014; 34:544-51. [PMID: 25026922 DOI: 10.1016/j.nutres.2014.04.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 04/04/2014] [Accepted: 04/18/2014] [Indexed: 02/03/2023]
Abstract
A precursor of protoporphyrin IX, 5-aminolevulinic acid (5-ALA) is used as a prodrug for photodiagnosis and photodynamic therapy. Recently, it has been shown that 5-ALA reduces glucose levels during fasting and after glucose loading in prediabetic subjects. We hypothesized that 5-ALA ameliorates diabetic conditions through mitochondrial changes in visceral adipose tissue. In order to explore the metabolic effects on the type 2 diabetic state, we administered ALA hydrochloride in combination with sodium ferrous citrate to Otsuka Long-Evans Tokushima Fatty (OLETF) rats at intragastric doses of 20 and 300 mg kg(-1) d(-1) for 6 weeks. The administration of 300 mg kg(-1) d(-1) of 5-ALA improved glucose intolerance, hypertriglyceridemia, and hyperleptinemia in OLETF rats more effectively than the administration of an equivalent dose of metformin, in accordance with reductions in food intake and body weight. Furthermore, the weight of the retroperitoneal fat tended to decrease and cellular mitochondrial content of the fat was markedly reduced by the 5-ALA administration, showing a positive correlation. These results suggest that 5-ALA ameliorates diabetic abnormalities in OLETF rats by reducing the visceral fat mass and mitochondrial content of adipocytes in a site-specific manner.
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Affiliation(s)
- Takashi Sato
- Biomaterial in Tokyo Co, Ltd, Tokyo, Japan; Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Toshinori Yasuzawa
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Ai Uesaka
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | | | | | | | - Yukiko Kobayashi
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Masashi Kuwahata
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Yasuhiro Kido
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.
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24
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Bruynsteen L, Erkens T, Peelman LJ, Ducatelle R, Janssens GPJ, Harris PA, Hesta M. Expression of inflammation-related genes is associated with adipose tissue location in horses. BMC Vet Res 2013; 9:240. [PMID: 24295090 PMCID: PMC4220830 DOI: 10.1186/1746-6148-9-240] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 11/27/2013] [Indexed: 12/13/2022] Open
Abstract
Background In humans, adipose tissue (AT) originating from different depots shows varying gene expression profiles. In horses, the risk of certain metabolic disorders may also be influenced by the impact of specific AT depots. Macrophage infiltration in human and rat AT is considered to be a source of inflammatory changes. In horses, this relationship has not been extensively studied yet. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), a useful method to evaluate differences in mRNA expression across different tissues, can be used to evaluate differences between equine AT depots. For a correct interpretation of the RT-qPCR results, expression data have to be normalized by the use of validated reference genes. The main objectives of this study were to compare mRNA expression of inflammation-related genes, as well as adipocyte morphology and number between different equine AT depots; and in addition, to investigate the presence of antigen presenting cells in equine AT and any potential relationship with adipokine mRNA expression. Results In this study, the mRNA expression of inflammation-related genes (leptin, chemokine ligand 5, interleukin 1β, interleukin 6, interleukin 10, adiponectin, matrix metalloproteinase 2, and superoxide dismutase 2) and candidate reference gene stability was investigated in 8 different AT depots collected from the nuchal, abdominal (mesenteric, retroperitoneal, and peri-renal) and subcutaneous (tail head and loin) AT region. By using GeNorm analysis, HPRT1, RPL32, and GAPDH were found to be the most stable genes in equine AT. The mRNA expression of leptin, chemokine ligand 5, interleukin 10, interleukin 1β, adiponectin, and matrix metalloproteinase 2 significantly differed across AT depots (P < 0.05). No significant AT depot effect was found for interleukin 6 and superoxide dismutase 2 (P > 0.05). Adipocyte area and number of antigen presenting cells per adipocyte significantly differed between AT depots (P < 0.05). Conclusions Adipose tissue location was associated with differences in mRNA expression of inflammation-related genes. This depot-specific difference in mRNA expression suggests that the overall inflammatory status of horses could be partially determined by the relative proportion of the different AT depots.
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Affiliation(s)
- Lien Bruynsteen
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, Merelbeke 9820, Belgium.
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25
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Harry H, Kan HE. Quantitative proton MR techniques for measuring fat. NMR IN BIOMEDICINE 2013; 26:1609-29. [PMID: 24123229 PMCID: PMC4001818 DOI: 10.1002/nbm.3025] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 07/13/2013] [Accepted: 08/19/2013] [Indexed: 05/09/2023]
Abstract
Accurate, precise and reliable techniques for the quantification of body and organ fat distributions are important tools in physiology research. They are critically needed in studies of obesity and diseases involving excess fat accumulation. Proton MR methods address this need by providing an array of relaxometry-based (T1, T2) and chemical shift-based approaches. These techniques can generate informative visualizations of regional and whole-body fat distributions, yield measurements of fat volumes within specific body depots and quantify fat accumulation in abdominal organs and muscles. MR methods are commonly used to investigate the role of fat in nutrition and metabolism, to measure the efficacy of short- and long-term dietary and exercise interventions, to study the implications of fat in organ steatosis and muscular dystrophies and to elucidate pathophysiological mechanisms in the context of obesity and its comorbidities. The purpose of this review is to provide a summary of mainstream MR strategies for fat quantification. The article succinctly describes the principles that differentiate water and fat proton signals, summarizes the advantages and limitations of various techniques and offers a few illustrative examples. The article also highlights recent efforts in the MR of brown adipose tissue and concludes by briefly discussing some future research directions.
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Affiliation(s)
- Houchun Harry
- Corresponding Author Houchun Harry Hu, PhD Children's Hospital Los Angeles University of Southern California 4650 Sunset Boulevard Department of Radiology, MS #81 Los Angeles, California, USA. 90027 , Office: +1 (323) 361-2688 Fax: +1 (323) 361-1510
| | - Hermien E. Kan
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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26
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de Godoy MRC, Swanson KS. COMPANION ANIMALS SYMPOSIUM: Nutrigenomics: Using gene expression and molecular biology data to understand pet obesity1. J Anim Sci 2013; 91:2949-64. [DOI: 10.2527/jas.2012-5860] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- M. R. C. de Godoy
- Department of Animal Sciences, University of Illinois, Urbana, IL 61801
| | - K. S. Swanson
- Department of Animal Sciences, University of Illinois, Urbana, IL 61801
- Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801
- Department of Veterinary Clinical Medicine, University of Illinois, Urbana, IL 61801
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27
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The cat as a model for human obesity: insights into depot-specific inflammation associated with feline obesity. Br J Nutr 2013; 110:1326-35. [DOI: 10.1017/s0007114513000226] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
According to human research, the location of fat accumulation seems to play an important role in the induction of obesity-related inflammatory complications. To evaluate whether an inflammatory response to obesity depends on adipose tissue location, adipokine gene expression, presence of immune cells and adipocyte cell size of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were compared between lean and obese cats. Additionally, the present study proposes the cat as a model for human obesity and highlights the importance of animal models for human research. A total of ten chronically obese and ten lean control cats were included in the present study. Body weight, body condition score and body composition were determined. T-lymphocyte, B-lymphocyte, macrophage concentrations and adipocyte cell size were measured in adipose tissue at different locations. Serum leptin concentration and the mRNA expression of leptin and adiponectin, monocyte chemoattractant protein-1, chemoligand-5, IL-8, TNF-α, interferon-γ, IL-6 and IL-10 were measured in blood and adipose tissues (abdominal and inguinal SAT, and omental, bladder and renal VAT). Feline obesity was characterised by increased adipocyte cell size and altered adipokine gene expression, in favour of pro-inflammatory cytokines and chemokines. Consequently, concentration of T-lymphocytes was increased in the adipose tissue of obese cats. Alteration of adipose tissue was location dependent in both lean and obese cats. Moreover, the observed changes were more prominent in SAT compared with VAT.
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28
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Kim SP. Mechanisms underlying restoration of hepatic insulin sensitivity with CB1 antagonism in the obese dog model. Adipocyte 2013; 2:47-49. [PMID: 23700552 PMCID: PMC3661137 DOI: 10.4161/adip.21890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Visceral fat has long been associated with the development of insulin resistance. Although the mechanism is not well understood, it has been suggested that an increase in this fat depot results in an elevation in portal vein levels of free fatty acids and/or adipokines, adversely affecting hepatic glucose production. Overactivity of the endocannabinoid system is closely related to abdominal obesity and type 2 diabetes, suggesting CB1 receptor antagonism may exert its beneficial effects by decreasing visceral fat mass. A recent study published from our laboratory explores the role of chronic CB1 receptor antagonism and the longitudinal changes in insulin sensitivity and fat deposition in the canine model.
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Affiliation(s)
- Stella P Kim
- Cedars-Sinai Medical Center; Diabetes and Obesity Research Center; Los Angeles, CA USA
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29
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Hu HH, Börnert P, Hernando D, Kellman P, Ma J, Reeder S, Sirlin C. ISMRM workshop on fat-water separation: insights, applications and progress in MRI. Magn Reson Med 2012; 68:378-88. [PMID: 22693111 PMCID: PMC3575097 DOI: 10.1002/mrm.24369] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/14/2012] [Accepted: 05/16/2012] [Indexed: 12/12/2022]
Abstract
Approximately 130 attendees convened on February 19-22, 2012 for the first ISMRM-sponsored workshop on water-fat imaging. The motivation to host this meeting was driven by the increasing number of research publications on this topic over the past decade. The scientific program included an historical perspective and a discussion of the clinical relevance of water-fat MRI, a technical description of multiecho pulse sequences, a review of data acquisition and reconstruction algorithms, a summary of the confounding factors that influence quantitative fat measurements and the importance of MRI-based biomarkers, a description of applications in the heart, liver, pancreas, abdomen, spine, pelvis, and muscles, an overview of the implications of fat in diabetes and obesity, a discussion on MR spectroscopy, a review of childhood obesity, the efficacy of lifestyle interventional studies, and the role of brown adipose tissue, and an outlook on federal funding opportunities from the National Institutes of Health.
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Affiliation(s)
- Houchun Harry Hu
- Departments of Radiology and Electrical Engineering, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California 90027, USA.
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