1
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Metz S, Krarup NT, Bryrup T, Støy J, Andersson EA, Christoffersen C, Neville MJ, Christiansen MR, Jonsson AE, Witte DR, Kampmann U, Nielsen LB, Jørgensen NR, Karpe F, Grarup N, Pedersen O, Kilpeläinen TO, Hansen T. The Arg82Cys polymorphism of the protein nepmucin implies a role in HDL metabolism. J Endocr Soc 2022; 6:bvac034. [PMID: 35382499 PMCID: PMC8974852 DOI: 10.1210/jendso/bvac034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Indexed: 12/02/2022] Open
Abstract
Context Blood lipid levels are linked to the risk of cardiovascular disease and regulated by genetic factors. A low-frequency polymorphism Arg82Cys (rs72836561) in the membrane protein nepmucin, encoded by CD300LG, is associated with lower fasting concentration of high-density lipoprotein cholesterol (HDLc) and higher fasting triglycerides. However, whether the variant is linked to postprandial lipids and glycemic status remains elusive. Objective Here, we augment the genetic effect of Arg82Cys on fasting plasma concentrations of HDL subclasses, postprandial lipemia after a standardized high-fat meal, and glycemic status to further untangle its role in HDL metabolism. Methods We elucidated fasting associations with HDL subclasses in a population-based cohort study (Oxford BioBank, OBB), including 4522 healthy men and women. We investigated fasting and postprandial consequences on HDL metabolism in recall-by-genotype (RbG) studies (fasting: 20 carrier/20 noncarrier; postprandial: 7 carrier/17 noncarrier), and shed light on the synergistic interaction with glycemic status. Results A lower fasting plasma concentration of cholesterol in large HDL particles was found in healthy male carriers of the Cys82 polymorphism compared to noncarriers, both in the OBB (P = .004) and RbG studies (P = .005). In addition, the Cys82 polymorphism was associated with low fasting plasma concentrations of ApoA1 (P = .008) in the OBB cohort. On the contrary, we did not find differences in postprandial lipemia or 2-hour plasma glucose levels. Conclusion Taken together, our results indicate an association between the Arg82Cys variant and a lower concentration of HDL particles and HDLc, especially in larger HDL subclasses, suggesting a link between nepmucin and HDLc metabolism or maturation.
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Affiliation(s)
- Sophia Metz
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nikolaj T Krarup
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Aalborg University Hospital, Department of Cardiology, Aalborg, Denmark
| | - Thomas Bryrup
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Julie Støy
- Aarhus University Hospital, Steno Diabetes Center Aarhus, Aarhus, Denmark
| | - Ehm A Andersson
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christina Christoffersen
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matt J Neville
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Malene R Christiansen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna E Jonsson
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Daniel R Witte
- Department of Public Health, Section of Epidemiology, Aarhus University, Denmark
| | - Ulla Kampmann
- Aarhus University Hospital, Steno Diabetes Center Aarhus, Aarhus, Denmark
| | - Lars B Nielsen
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
- Faculty of Health, Aarhus University, Aarhus, Denmark
| | - Niklas R Jørgensen
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen Denmark
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Niels Grarup
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Oluf Pedersen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tuomas O Kilpeläinen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Torben Hansen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Faculty of Health, University of Southern Denmark, Odense, Denmark
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2
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Mascalzoni D, Biasiotto R, Borsche M, Brüggemann N, De Grandi A, Goegele M, Frygner-Holm S, Klein C, Kösters M, Staunton C, Pramstaller PP, Krawczak M, Hicks AA. Balancing scientific interests and the rights of participants in designing a recall by genotype study. Eur J Hum Genet 2021; 29:1146-1157. [PMID: 33981014 PMCID: PMC8298596 DOI: 10.1038/s41431-021-00860-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/15/2020] [Accepted: 03/02/2021] [Indexed: 01/14/2023] Open
Abstract
Recall by genotype (RbG) studies aim to better understand the phenotypes that correspond to genetic variants of interest, by recruiting carriers of such variants for further phenotyping. RbG approaches pose major ethical and legal challenges related to the disclosure of possibly unwanted genetic information. The Cooperative Health Research in South Tyrol (CHRIS) study is a longitudinal cohort study based in South Tyrol, Italy. Demand has grown for CHRIS study participants to be enrolled in RbG studies, thus making the design of a suitable ethical framework a pressing need. We here report upon the design of a pilot RbG study conducted with CHRIS study participants. By reviewing the literature and by consulting relevant stakeholders (CHRIS participants, clinical geneticists, ethics board, GPs), we identified key ethical issues in RbG approaches (e.g. complexity of the context, communication of genetic results, measures to further protect participants). The design of the pilot was based on a feasibility assessment, the selection of a suitable test case within the ProtectMove Research Unit on reduced penetrance of hereditary movement disorders, and the development of appropriate recruitment and communication strategies. An empirical study was embedded in the pilot study with the aim of understanding participants' views on RbG. Our experience with the pilot study in CHRIS allowed us to contribute to the development of best practices and policies for RbG studies by drawing recommendations: addressing the possibility of RbG in the original consent, implementing tailored communication strategies, engaging stakeholders, designing embedded empirical studies, and sharing research experiences and methodology.
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Affiliation(s)
- Deborah Mascalzoni
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy.
- Department of Public Health and Caring Sciences, Center for Research Ethics and Bioethics, Uppsala University, Uppsala, Sweden.
| | - Roberta Biasiotto
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | - Max Borsche
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Department of Neurology, University Medical Center Schleswig-Holstein, Lübeck, Germany
| | - Norbert Brüggemann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Department of Neurology, University Medical Center Schleswig-Holstein, Lübeck, Germany
| | - Alessandro De Grandi
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | - Martin Goegele
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | | | - Christine Klein
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Maria Kösters
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | - Ciara Staunton
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
- School of Law, Middlesex University, London, UK
| | - Peter P Pramstaller
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Kiel University, Kiel, Germany
| | - Andrew A Hicks
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
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3
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Fang H, Chen L, Knight JC. From genome-wide association studies to rational drug target prioritisation in inflammatory arthritis. THE LANCET. RHEUMATOLOGY 2020; 2:e50-e62. [PMID: 38258277 DOI: 10.1016/s2665-9913(19)30134-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/04/2019] [Accepted: 11/08/2019] [Indexed: 12/24/2022]
Abstract
Early identification of genetically validated drug targets can increase the chances of successful late-stage drug development. 81 high-quality genome-wide association studies (GWAS) in diseases related to inflammatory arthritis have been curated into the GWAS catalogue; however, translation of genetic findings from GWAS into rational drug target discovery has been poor. No human genetic findings have completely driven drug development for inflammatory arthritis; however, genetic associations have partly driven the development of abatacept (CTLA-4-Ig) in rheumatoid arthritis and secukinumab (anti-IL-23R) in ankylosing spondylitis. Roadblocks to progress exist, including little knowledge of the genetic architecture and regulatory mechanisms underlying associations, and the need to identify gene regulatory networks and assess target tractability. New opportunities are arising that could maximise the informativeness of GWAS for drug target validation. Genetic variants can be linked to core genes by using functional genomics and then to peripheral genes interconnected to core genes using network information. Moreover, identification of crosstalk between biological pathways might highlight key points for therapeutic intervention.
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Affiliation(s)
- Hai Fang
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Liye Chen
- Botnar Research Centre, University of Oxford, Oxford, UK
| | - Julian C Knight
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
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4
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Associations between circulating fatty acid levels and metabolic risk factors. JOURNAL OF NUTRITION & INTERMEDIARY METABOLISM 2019. [DOI: 10.1016/j.jnim.2019.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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5
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Karpe F, Vasan SK, Humphreys SM, Miller J, Cheeseman J, Dennis AL, Neville MJ. Cohort Profile: The Oxford Biobank. Int J Epidemiol 2019; 47:21-21g. [PMID: 29040543 PMCID: PMC5837504 DOI: 10.1093/ije/dyx132] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2017] [Indexed: 11/18/2022] Open
Affiliation(s)
- Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford.,Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Senthil K Vasan
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford
| | - Sandy M Humphreys
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford.,Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - John Miller
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford.,Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Jane Cheeseman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford.,Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - A Louise Dennis
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford.,Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Matt J Neville
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford.,Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK
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6
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Turning over our fat stores: the key to metabolic health Blaxter Award Lecture 2018. Proc Nutr Soc 2018; 78:398-406. [DOI: 10.1017/s0029665118002598] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The present paper results from my receiving the Nutrition Society's first Blaxter Award, and describes briefly my academic history. My interest in human fat metabolism began in the Medical Research Council's Trauma Unit, studying metabolic changes in critically ill patients and their responses to nutrition. On moving to Oxford in 1986, I began to study pathways for depositing fat in adipose tissue. This involved the development of new methodologies, in particular, a technique for measurement of arterio-venous differences of metabolite concentrations across human adipose tissue beds, primarily the subcutaneous anterior abdominal depot. Our early studies showed that this tissue is dynamic in its metabolic behaviour, responding rapidly (within minutes) to changes in nutritional state. This led to an understanding of adipose tissue as playing an essential role in metabolic health, by capturing incoming dietary fatty acids, storing them as TAG and releasing them when needed, analogous to the role of the liver in glucose metabolism; we called this ‘buffering’ of fatty acid fluxes. In obesity, the mass of adipose tissue expands considerably, more than is often appreciated from BMI values. We confirmed other observations of a strong suppression of release of NEFA from adipose tissue in obesity, tending to normalise circulating NEFA concentrations. A corollary, however, is that fatty acid uptake must be equally suppressed, and this disrupts the ‘buffering’ capacity of adipose tissue, leading to fat deposition in other tissues; ectopic fat deposition. This, in turn, is associated with many metabolic abnormalities linked to obesity.
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7
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Alver M, Palover M, Saar A, Läll K, Zekavat SM, Tõnisson N, Leitsalu L, Reigo A, Nikopensius T, Ainla T, Kals M, Mägi R, Gabriel SB, Eha J, Lander ES, Irs A, Philippakis A, Marandi T, Natarajan P, Metspalu A, Kathiresan S, Esko T. Recall by genotype and cascade screening for familial hypercholesterolemia in a population-based biobank from Estonia. Genet Med 2018; 21:1173-1180. [PMID: 30270359 PMCID: PMC6443485 DOI: 10.1038/s41436-018-0311-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 09/06/2018] [Indexed: 01/13/2023] Open
Abstract
Purpose Large-scale, population-based biobanks integrating health records and genomic profiles may provide a platform to identify individuals with disease-predisposing genetic variants. Here, we recall probands carrying familial hypercholesterolemia (FH)-associated variants, perform cascade screening of family members, and describe health outcomes affected by such a strategy. Methods The Estonian Biobank of Estonian Genome Center, University of Tartu, comprises 52,274 individuals. Among 4776 participants with exome or genome sequences, we identified 27 individuals who carried FH-associated variants in the LDLR, APOB, or PCSK9 genes. Cascade screening of 64 family members identified an additional 20 carriers of FH-associated variants. Results Via genetic counseling and clinical management of carriers, we were able to reclassify 51% of the study participants from having previously established nonspecific hypercholesterolemia to having FH and identify 32% who were completely unaware of harboring a high-risk disease-associated genetic variant. Imaging-based risk stratification targeted 86% of the variant carriers for statin treatment recommendations. Conclusion Genotype-guided recall of probands and subsequent cascade screening for familial hypercholesterolemia is feasible within a population-based biobank and may facilitate more appropriate clinical management.
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Affiliation(s)
- Maris Alver
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia.,Department of Biotechnology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Marili Palover
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia.,Department of Biotechnology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Aet Saar
- Department of Cardiology, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Cardiology Centre, North Estonia Medical Centre, Tallinn, Estonia
| | - Kristi Läll
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia.,Institute of Mathematics and Statistics, University of Tartu, Tartu, Estonia
| | - Seyedeh Maryam Zekavat
- Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Yale School of Medicine, New Haven, CT, USA
| | - Neeme Tõnisson
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia.,Department of Clinical Genetics in Tallinn, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - Liis Leitsalu
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Anu Reigo
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Tiit Nikopensius
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Tiia Ainla
- Department of Cardiology, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Cardiology Centre, North Estonia Medical Centre, Tallinn, Estonia
| | - Mart Kals
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia.,Institute of Mathematics and Statistics, University of Tartu, Tartu, Estonia
| | - Reedik Mägi
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | | | - Jaan Eha
- Department of Cardiology, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Heart Clinic, Tartu University Hospital, Tartu, Estonia
| | - Eric S Lander
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Alar Irs
- Heart Clinic, Tartu University Hospital, Tartu, Estonia
| | | | - Toomas Marandi
- Department of Cardiology, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Cardiology Centre, North Estonia Medical Centre, Tallinn, Estonia
| | - Pradeep Natarajan
- Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Cardiovascular Research Center and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Andres Metspalu
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia.,Department of Biotechnology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Sekar Kathiresan
- Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Cardiovascular Research Center and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Tõnu Esko
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia. .,Broad Institute of Harvard and MIT, Cambridge, MA, USA.
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8
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Kamble PG, Pereira MJ, Gustafsson S, Lundkvist P, Castillejo-López C, Fall T, Ingelsson E, Eriksson JW. Role of peroxisome proliferator-activated receptor gamma Pro12Ala polymorphism in human adipose tissue: assessment of adipogenesis and adipocyte glucose and lipid turnover. Adipocyte 2018; 7:285-296. [PMID: 30064293 PMCID: PMC6768277 DOI: 10.1080/21623945.2018.1503030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The protective mechanisms of peroxisome proliferator-activated receptor gamma (PPARγ) Pro12Ala polymorphism in type 2 diabetes (T2D) are unclear. We obtained subcutaneous adipose tissue (AT) before and 3 h after oral glucose (OGTT) in carriers and non-carriers of the Ala allele (12 Pro/Pro, 15 Pro/Ala, and 13 Ala/Ala). Adipogenesis, adipocyte glucose uptake and lipolysis as well as PPARγ target gene expression were investigated and compared between the genotype groups. During fasting and post-OGTT, neither basal nor insulin-stimulated adipocyte glucose uptake differed between genotypes. Compared to fasting, a decreased hormone-sensitive lipase gene expression in Pro/Pro (p < 0.05) was accompanied with a higher antilipolytic effect of insulin post-OGTT (p < 0.01). The adipocyte size was similar across groups. Preadipocyte differentiation rates between Pro/Pro and Ala/Ala were unchanged. In conclusion, no major differences in AT differentiation, glucose uptake, lipolysis or expression of PPARγ target genes were observed between different PPARγ Pro12Ala genotypes. Albeit small, our study may suggest that other pathways in AT or effects exerted in other tissues might contribute to the Pro12Ala-mediated protection against T2D.
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Affiliation(s)
- Prasad G. Kamble
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Maria J. Pereira
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Stefan Gustafsson
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Per Lundkvist
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Casimiro Castillejo-López
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Tove Fall
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Erik Ingelsson
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Jan W. Eriksson
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
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9
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Franks PW, Timpson NJ. Genotype-Based Recall Studies in Complex Cardiometabolic Traits. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2018; 11:e001947. [PMID: 30354344 PMCID: PMC6813040 DOI: 10.1161/circgen.118.001947] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In genotype-based recall (GBR) studies, people (or their biological samples) who carry genotypes of special interest for a given hypothesis test are recalled from a larger cohort (or biobank) for more detailed investigations. There are several GBR study designs that offer a range of powerful options to elucidate (1) genotype-phenotype associations (by increasing the efficiency of genetic association studies, thereby allowing bespoke phenotyping in relatively small cohorts), (2) the effects of environmental exposures (within the Mendelian randomization framework), and (3) gene-treatment interactions (within the setting of GBR interventional trials). In this review, we overview the literature on GBR studies as applied to cardiometabolic health outcomes. We also review the GBR approaches used to date and outline new methods and study designs that might enhance the utility of GBR-focused studies. Specifically, we highlight how GBR methods have the potential to augment randomized controlled trials, providing an alternative application for the now increasingly accepted Mendelian randomization methods usually applied to large-scale population-based data sets. Further to this, we consider how functional and basic science approaches alongside GBR designs offer intellectually intriguing and potentially powerful ways to explore the implications of alterations to specific (and potentially druggable) biological pathways.
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Affiliation(s)
- Paul W Franks
- Department of Clinical Sciences, Genetic and Molecular Epidemiology Unit, Lund University Diabetes Centre, Skåne University Hospital, SE-21741, Malmö, Sweden
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford
- Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA, USA
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Nicholas J Timpson
- MRC Integrative Epidemiology Unit, Avon Longitudinal Study of Parents and Children, Population Health Science, Bristol Medical School, Oakfield House, Oakfield Grove, Bristol, BS8 2BN, UK
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10
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Corbin LJ, Tan VY, Hughes DA, Wade KH, Paul DS, Tansey KE, Butcher F, Dudbridge F, Howson JM, Jallow MW, John C, Kingston N, Lindgren CM, O'Donavan M, O'Rahilly S, Owen MJ, Palmer CNA, Pearson ER, Scott RA, van Heel DA, Whittaker J, Frayling T, Tobin MD, Wain LV, Smith GD, Evans DM, Karpe F, McCarthy MI, Danesh J, Franks PW, Timpson NJ. Formalising recall by genotype as an efficient approach to detailed phenotyping and causal inference. Nat Commun 2018; 9:711. [PMID: 29459775 PMCID: PMC5818506 DOI: 10.1038/s41467-018-03109-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/19/2018] [Indexed: 02/02/2023] Open
Abstract
Detailed phenotyping is required to deepen our understanding of the biological mechanisms behind genetic associations. In addition, the impact of potentially modifiable risk factors on disease requires analytical frameworks that allow causal inference. Here, we discuss the characteristics of Recall-by-Genotype (RbG) as a study design aimed at addressing both these needs. We describe two broad scenarios for the application of RbG: studies using single variants and those using multiple variants. We consider the efficacy and practicality of the RbG approach, provide a catalogue of UK-based resources for such studies and present an online RbG study planner.
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Affiliation(s)
- Laura J Corbin
- MRC Integrative Epidemiology Unit at University of Bristol, Bristol, BS8 2BN, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, BS8 2BN, UK
| | - Vanessa Y Tan
- MRC Integrative Epidemiology Unit at University of Bristol, Bristol, BS8 2BN, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, BS8 2BN, UK
| | - David A Hughes
- MRC Integrative Epidemiology Unit at University of Bristol, Bristol, BS8 2BN, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, BS8 2BN, UK
| | - Kaitlin H Wade
- MRC Integrative Epidemiology Unit at University of Bristol, Bristol, BS8 2BN, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, BS8 2BN, UK
| | - Dirk S Paul
- MRC/BHF Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, CB1 8RN, UK
- British Heart Foundation (BHF) Centre of Excellence, Division of Cardiovascular Medicine, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Katherine E Tansey
- Core Bioinformatics and Statistics Team, College of Biomedical & Life Sciences, Cardiff University, Cardiff, CF10 3XQ, UK
| | - Frances Butcher
- Oxford School of Public Health, University of Oxford, Oxford, OX3 7LF, UK
| | - Frank Dudbridge
- Department of Health Sciences, University of Leicester, Leicester, LE1 7RH, UK
| | - Joanna M Howson
- MRC/BHF Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, CB1 8RN, UK
| | - Momodou W Jallow
- Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- MRC Unit The Gambia (MRCG), Atlantic Boulevard, Fajara, P.O. Box 273, Banjul, Gambia
| | - Catherine John
- Department of Health Sciences, University of Leicester, Leicester, LE1 7RH, UK
| | - Nathalie Kingston
- National Institute for Health Research (NIHR) BioResource for Translational Research in Common and Rare Diseases & NIHR BioResource Centre Cambridge, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Cecilia M Lindgren
- Big Data Institute at the Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7FZ, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, 02142, USA
- NIHR Oxford Biomedical Research Centre, OUH Hospital, Oxford, OX4 2PG, UK
| | - Michael O'Donavan
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, CF24 4HQ, UK
| | - Stephen O'Rahilly
- Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Michael J Owen
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, CF24 4HQ, UK
| | - Colin N A Palmer
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY, UK
| | - Ewan R Pearson
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY, UK
| | - Robert A Scott
- Quantitative Sciences, GlaxoSmithKline, Stevenage, SG1 2NY, UK
| | - David A van Heel
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - John Whittaker
- Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- Statistical Genetics, Projects, Clinical Platforms, and Sciences (PCPS), GlaxoSmithKline, Research Triangle Park, NC, 27709, USA
| | - Tim Frayling
- Genetics of Complex Traits, Institute of Biomedical and Clinical Science, University of Exeter Medical School, Royal Devon and Exeter Hospital, Exeter, EX1 2LU, UK
| | - Martin D Tobin
- Department of Health Sciences, University of Leicester, Leicester, LE1 7RH, UK
- NIHR Leicester Biomedical Research Centre, Glenfield Hospital, Leicester, LE3 9QP, UK
| | - Louise V Wain
- Department of Health Sciences, University of Leicester, Leicester, LE1 7RH, UK
- NIHR Leicester Biomedical Research Centre, Glenfield Hospital, Leicester, LE3 9QP, UK
| | - George Davey Smith
- MRC Integrative Epidemiology Unit at University of Bristol, Bristol, BS8 2BN, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, BS8 2BN, UK
| | - David M Evans
- MRC Integrative Epidemiology Unit at University of Bristol, Bristol, BS8 2BN, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, BS8 2BN, UK
- The University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD, 4072, Australia
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 7LE, UK
- NIHR Oxford Biomedical Research Centre, Churchill Hospital, Oxford, OX3 7LE, UK
| | - Mark I McCarthy
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 7LE, UK
- NIHR Oxford Biomedical Research Centre, Churchill Hospital, Oxford, OX3 7LE, UK
| | - John Danesh
- MRC/BHF Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, CB1 8RN, UK
- British Heart Foundation (BHF) Centre of Excellence, Division of Cardiovascular Medicine, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1HH, UK
- NIHR Blood and Transplant Research Unit in Donor Health and Genomics, Department of Public Health and Primary Care, University of Cambridge, Cambridge, CB2 0SR, UK
| | - Paul W Franks
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 7LE, UK
- Department of Clinical Sciences, Genetic and Molecular Epidemiology Unit, Clinical Research Centre, Lund University, Skåne University Hospital, Malmö, SE-205 02, Sweden
- Department of Public Health and Clinical Medicine, Section for Medicine, Umeå University, Umeå, 907 37, Sweden
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Nicholas J Timpson
- MRC Integrative Epidemiology Unit at University of Bristol, Bristol, BS8 2BN, UK.
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, BS8 2BN, UK.
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11
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Vasan SK, Osmond C, Canoy D, Christodoulides C, Neville MJ, Di Gravio C, Fall CHD, Karpe F. Comparison of regional fat measurements by dual-energy X-ray absorptiometry and conventional anthropometry and their association with markers of diabetes and cardiovascular disease risk. Int J Obes (Lond) 2017; 42:850-857. [PMID: 29151596 PMCID: PMC5965665 DOI: 10.1038/ijo.2017.289] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/06/2017] [Accepted: 11/06/2017] [Indexed: 01/05/2023]
Abstract
Background/Objectives: Fat distribution is a strong and independent predictor of type 2 diabetes (T2D) and cardiovascular disease (CVD) and is usually determined using conventional anthropometry in epidemiological studies. Dual-energy X-ray absorptiometry (DXA) can measure total and regional adiposity more accurately. Nonetheless, whether DXA provides more precise estimates of cardiovascular risk in relation to total and regional adiposity is not known. We determined the strength of the associations between DXA- and conventional anthropometry determined fat distribution and T2D and CVD risk markers. Subjects/Methods: Waist (WC) and hip circumference (HC) and DXA was used to measure total and regional adiposity in 4950 (2119 men) participants aged 29–55 years from the Oxford Biobank without pre-existing T2D or CVD. Cross-sectional associations were compared between WC and HC vs. DXA-determined regional adiposity (all z-score normalised) with impaired fasting glucose, hypertriglyceridemia, hypertension and insulin resistance (IR). Results: Following adjustment for total adiposity, upper body adiposity measurements showed consistently increased risk of T2D and CVD risk markers except for abdominal subcutaneous fat in both sexes, and arm fat in men, which showed protective associations. Among upper adiposity depots, visceral fat mass showed stronger odds ratios (OR) ranging from 1.69 to 3.64 compared with WC 1.07–1.83. Among lower adiposity depots, HC showed modest protection for IR in both sexes (men: OR 0.80 (95% confidence interval 0.67, 0.96); women: 0.69 (0.56, 0.86)), whereas gynoid fat and in particular leg fat showed consistent and strong protective effects for all outcomes in both men and women. The differential effect of body fat distribution on CVD and T2D were more pronounced at higher levels of total adiposity. Conclusions: Compared with DXA, conventional anthropometry underestimates the associations of regional adiposity with T2D and CVD risk markers. After correcting for overall adiposity, greater subcutaneous fat mass in particular in the lower body is protective relative to greater android or visceral adipose tissue mass.
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Affiliation(s)
- S K Vasan
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - C Osmond
- MRC Life-course Epidemiology Unit, University of Southampton, Southampton, UK
| | - D Canoy
- Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - C Christodoulides
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - M J Neville
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK.,NIHR Oxford Biomedical Centre, Oxford University Hospital Trust and University of Oxford, Oxford, UK
| | - C Di Gravio
- MRC Life-course Epidemiology Unit, University of Southampton, Southampton, UK
| | - C H D Fall
- MRC Life-course Epidemiology Unit, University of Southampton, Southampton, UK
| | - F Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK.,NIHR Oxford Biomedical Centre, Oxford University Hospital Trust and University of Oxford, Oxford, UK
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12
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Kamble PG, Gustafsson S, Pereira MJ, Lundkvist P, Cook N, Lind L, Franks PW, Fall T, Eriksson JW, Ingelsson E. Genotype-based recall to study metabolic effects of genetic variation: a pilot study of PPARG Pro12Ala carriers. Ups J Med Sci 2017; 122:234-242. [PMID: 29303622 PMCID: PMC5810227 DOI: 10.1080/03009734.2017.1405127] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
AIM To assess practical implications of genotype-based recall (GBR) studies, an increasingly popular approach for in-depth characterization of genotype-phenotype relationships. METHODS We genotyped 2500 participants from the Swedish EpiHealth cohort and considered loss-of-function and missense variants in genes with relation to cardiometabolic traits as the basis for our GBR study. Therefore, we focused on carriers and non-carriers of the PPARG Pro12Ala (rs1801282) variant, as it is a relatively common variant with a minor allele frequency (MAF) of 0.14. It has also been shown to affect ligand binding and transcription, and carriage of the minor allele (Ala12) is associated with a reduced risk of type 2 diabetes. We re-invited 39 Pro12Pro, 34 Pro12Ala, and 30 Ala12Ala carriers and performed detailed anthropometric and serological assessments. RESULTS The participation rates in the GBR study were 31%, 44%, and 40%, and accordingly we included 12, 15, and 13 individuals with Pro12Pro, Pro12Ala, and Ala12Ala variants, respectively. There were no differences in anthropometric or metabolic variables among the different genotype groups. CONCLUSIONS Our report highlights that from a practical perspective, GBR can be used to study genotype-phenotype relationships. This approach can prove to be a valuable tool for follow-up findings from large-scale genetic discovery studies by undertaking detailed phenotyping procedures that might not be feasible in large studies. However, our study also illustrates the need for a larger pool of genotyped or sequenced individuals to allow for selection of rare variants with larger effects that can be examined in a GBR study of the present size.
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Affiliation(s)
- Prasad G. Kamble
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Sweden
| | - Stefan Gustafsson
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Sweden
| | - Maria J. Pereira
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Sweden
| | - Per Lundkvist
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Sweden
| | - Naomi Cook
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Sweden
| | - Lars Lind
- Department of Medical Sciences, Molecular Epidemiology, EpiHealth, Uppsala University, Sweden
| | - Paul W. Franks
- Department of Clinical Sciences, Genetic and Molecular Epidemiology Unit, Lund University Diabetes Centre, Malmö, Sweden
| | - Tove Fall
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Sweden
| | - Jan W. Eriksson
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Sweden
| | - Erik Ingelsson
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Sweden
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, USA
- CONTACT Erik Ingelsson Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Dr, Stanford, CA 94305, USA
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13
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Neville MJ, Lee W, Humburg P, Wong D, Barnardo M, Karpe F, Knight JC. High resolution HLA haplotyping by imputation for a British population bioresource. Hum Immunol 2017; 78:242-251. [PMID: 28111166 PMCID: PMC5367449 DOI: 10.1016/j.humimm.2017.01.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 12/03/2016] [Accepted: 01/17/2017] [Indexed: 12/02/2022]
Abstract
This study aimed to establish the occurrence and frequency of HLA alleles and haplotypes for a healthy British Caucasian population bioresource from Oxfordshire. We present the results of imputation from HLA SNP genotyping data using SNP2HLA for 5553 individuals from Oxford Biobank, defining one- and two-field alleles together with amino acid polymorphisms. We show that this achieves a high level of accuracy with validation using sequence-specific primer amplification PCR. We define six- and eight-locus HLA haplotypes for this population by Bayesian methods implemented using PHASE. We determine patterns of linkage disequilibrium and recombination for these individuals involving classical HLA loci and show how analysis within a haplotype block structure may be more tractable for imputed data. Our findings contribute to knowledge of HLA diversity in healthy populations and further validate future large-scale use of HLA imputation as an informative approach in population bioresources.
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Affiliation(s)
- Matt J Neville
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Old Road, Oxford OX3 7LJ, UK; Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Wanseon Lee
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Peter Humburg
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Daniel Wong
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Martin Barnardo
- Transplant Immunology and Immunogenetics Laboratory, Oxford Transplant Centre, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Old Road, Oxford OX3 7LJ, UK; Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Julian C Knight
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
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14
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Pramfalk C, Pavlides M, Banerjee R, McNeil CA, Neubauer S, Karpe F, Hodson L. Fasting Plasma Insulin Concentrations Are Associated With Changes in Hepatic Fatty Acid Synthesis and Partitioning Prior to Changes in Liver Fat Content in Healthy Adults. Diabetes 2016; 65:1858-67. [PMID: 27207513 DOI: 10.2337/db16-0236] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/12/2016] [Indexed: 11/13/2022]
Abstract
Resistance to the action of insulin affects fatty acid delivery to the liver, fatty acid synthesis and oxidation within the liver, and triglyceride export from the liver. To understand the metabolic consequences of hepatic fatty acid synthesis, partitioning, oxidation, and net liver fat content in the fasted and postprandial states, we used stable-isotope tracer methodologies to study healthy men and women with varying degrees of insulin resistance before and after consumption of a mixed meal. Subjects were classified as being normoinsulinemic (NI) (fasting plasma insulin <11.2 mU/L, n = 18) or hyperinsulinemic (HI) (fasting plasma insulin >11.2 mU/L, n = 19). Liver fat content was similar between HI and NI individuals, despite HI subjects having marginally more visceral fat. However, de novo lipogenesis was higher and fatty acid oxidation was lower in HI individuals compared with NI subjects. These data suggest that metabolic pathways promoting fat accumulation are enhanced in HI but, paradoxically, without any significant effect on liver fat content when observed in healthy people. This is likely to be explained by increased triglyceride secretion as observed by hypertriglyceridemia.
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Affiliation(s)
- Camilla Pramfalk
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, U.K
| | - Michael Pavlides
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, U.K. Translational Gastroenterology Unit, John Radcliffe Hospital, Oxford, U.K
| | - Rajarshi Banerjee
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, U.K
| | - Catriona A McNeil
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, U.K
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, U.K
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, U.K. National Institute for Health Research Oxford Biomedical Research Centre, Oxford University Hospital Trusts, Oxford, U.K
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, U.K.
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15
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Abstract
The genome is often the conduit through which environmental exposures convey their effects on health and disease. Whilst not all diseases act by directly perturbing the genome, the phenotypic responses are often genetically determined. Hence, whilst diseases are often defined has having differing degrees of genetic determination, genetic and environmental factors are, with few exceptions, inseparable features of most diseases, not least type 2 diabetes. It follows that to optimize diabetes, prevention and treatment will require that the etiological roles of genetic and environmental risk factors be jointly considered. As we discuss here, studies focused on quantifying gene-environment and gene-treatment interactions are gathering momentum and may eventually yield data that helps guide health-related choices and medical interventions for type 2 diabetes and other complex diseases.
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Affiliation(s)
- Paul W Franks
- Genetic and Molecular Epidemiology Unit, Lund University Diabetes Center, Department of Clinical Sciences, Clinical Research Center, Skåne University Hospital Malmö, Lund University, Building 91, Level 10, Jan Waldenströms gata 35, 205 02, Malmö, Sweden.
- Department of Public Health and Clinical Medicine, Umeå University, 90188, Umeå, Sweden.
- Department of Nutrition, Harvard School of Public Health, Boston, MA, 02115, USA.
| | - Guillaume Paré
- Population Health Research Institute, McMaster University, Hamilton General Hospital Campus, DB-CVSRI, 237 Barton Street East, Room C3103, Hamilton, ON, L8L 2X2, Canada
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
- Department of Clinical Epidemiology and Biostatistics, Population Genomics Program, McMaster University, Hamilton, ON, Canada
- Thrombosis and Atherosclerosis Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, ON, Canada
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16
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Pramfalk C, Pavlides M, Banerjee R, McNeil CA, Neubauer S, Karpe F, Hodson L. Sex-Specific Differences in Hepatic Fat Oxidation and Synthesis May Explain the Higher Propensity for NAFLD in Men. J Clin Endocrinol Metab 2015; 100:4425-33. [PMID: 26414963 PMCID: PMC4667166 DOI: 10.1210/jc.2015-2649] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
CONTEXT AND OBJECTIVE In most populations a greater proportion of men have hepatic steatosis than women. Sex-specific differences in hepatic dietary fatty acid (FA) metabolism have not been well characterized. We compared fasting and postprandial hepatic FA synthesis (de novo lipogenesis [DNL]) and oxidation in men and women. PARTICIPANTS AND METHODS Fasting and postprandial hepatic FA metabolism was studied in 22 healthy men (n = 11) and women with similar age, body mass index, and liver fat content using metabolic substrates labeled with stable-isotope tracers ((2)H2O and [U(13)C]palmitate). Dietary FA oxidation was assessed by appearance of (13)C into plasma 3-hydroxybutyrate and breath CO2 as markers of liver and whole-body FA oxidation, respectively. RESULTS Despite similar liver fat content, fasting and postprandial plasma triacylglycerol (TG) concentrations were significantly (P < .05) higher in men compared with women. The appearance of (13)C from dietary FA into plasma 3-hydroxybutyrate and breath CO2 was greater (P < .05) in women compared with men. Although the contribution of DNL into very low-density lipoprotein (VLDL)-TG was similar (∼ 10%) in the fasting state, there was a divergence in pattern over the course of the study, with men maintaining a higher contribution of DNL to VLDL-TG than women (P = .006 time x sex interaction). CONCLUSIONS The combination of lower dietary FA oxidation and a prolonged increase in DNL observed in men may represent partitioning of FA into esterification and storage pathways within the liver, leading to greater VLDL-TG production, and predispose to the sex difference in hepatic steatosis.
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Affiliation(s)
- Camilla Pramfalk
- Oxford Centre for Diabetes, Endocrinology, and Metabolism (C.P., C.A.M., F.K., L.H.), Oxford Centre for Clinical Magnetic Resonance Research (M.P., R.B., S.N.), University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Translational Gastroenterology Unit (M.P.), John Radcliffe Hospital and National Institute for Health Research Oxford Biomedical Research Centre (F.K.), Oxford University Hospital Trusts, Oxford OX3 9DU, United Kingdom
| | - Michael Pavlides
- Oxford Centre for Diabetes, Endocrinology, and Metabolism (C.P., C.A.M., F.K., L.H.), Oxford Centre for Clinical Magnetic Resonance Research (M.P., R.B., S.N.), University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Translational Gastroenterology Unit (M.P.), John Radcliffe Hospital and National Institute for Health Research Oxford Biomedical Research Centre (F.K.), Oxford University Hospital Trusts, Oxford OX3 9DU, United Kingdom
| | - Rajarshi Banerjee
- Oxford Centre for Diabetes, Endocrinology, and Metabolism (C.P., C.A.M., F.K., L.H.), Oxford Centre for Clinical Magnetic Resonance Research (M.P., R.B., S.N.), University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Translational Gastroenterology Unit (M.P.), John Radcliffe Hospital and National Institute for Health Research Oxford Biomedical Research Centre (F.K.), Oxford University Hospital Trusts, Oxford OX3 9DU, United Kingdom
| | - Catriona A McNeil
- Oxford Centre for Diabetes, Endocrinology, and Metabolism (C.P., C.A.M., F.K., L.H.), Oxford Centre for Clinical Magnetic Resonance Research (M.P., R.B., S.N.), University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Translational Gastroenterology Unit (M.P.), John Radcliffe Hospital and National Institute for Health Research Oxford Biomedical Research Centre (F.K.), Oxford University Hospital Trusts, Oxford OX3 9DU, United Kingdom
| | - Stefan Neubauer
- Oxford Centre for Diabetes, Endocrinology, and Metabolism (C.P., C.A.M., F.K., L.H.), Oxford Centre for Clinical Magnetic Resonance Research (M.P., R.B., S.N.), University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Translational Gastroenterology Unit (M.P.), John Radcliffe Hospital and National Institute for Health Research Oxford Biomedical Research Centre (F.K.), Oxford University Hospital Trusts, Oxford OX3 9DU, United Kingdom
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology, and Metabolism (C.P., C.A.M., F.K., L.H.), Oxford Centre for Clinical Magnetic Resonance Research (M.P., R.B., S.N.), University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Translational Gastroenterology Unit (M.P.), John Radcliffe Hospital and National Institute for Health Research Oxford Biomedical Research Centre (F.K.), Oxford University Hospital Trusts, Oxford OX3 9DU, United Kingdom
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology, and Metabolism (C.P., C.A.M., F.K., L.H.), Oxford Centre for Clinical Magnetic Resonance Research (M.P., R.B., S.N.), University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Translational Gastroenterology Unit (M.P.), John Radcliffe Hospital and National Institute for Health Research Oxford Biomedical Research Centre (F.K.), Oxford University Hospital Trusts, Oxford OX3 9DU, United Kingdom
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17
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Pihlajamäki J, Schwab U, Kaminska D, Ågren J, Kuusisto J, Kolehmainen M, Paananen J, Laakso M, Uusitupa M. Dietary polyunsaturated fatty acids and the Pro12Ala polymorphisms of PPARG regulate serum lipids through divergent pathways: a randomized crossover clinical trial. GENES AND NUTRITION 2015; 10:43. [PMID: 26446033 DOI: 10.1007/s12263-015-0493-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 09/25/2015] [Indexed: 02/05/2023]
Abstract
Human and animal studies suggest an interaction between the Pro12Ala polymorphism of PPARG and dietary fat. In this randomized crossover clinical trial, we investigated whether subjects with the Pro12Pro and Ala12Ala genotypes of PPARG respond differently to a diet supplemented with high saturated (SAFA) or polyunsaturated fatty acid (PUFA).We recruited non-diabetic men from a population-based METSIM study (including 10,197 men) to obtain men with the Ala12Ala and the Pro12Pro genotypes matched for age and body mass index. Seventeen men with the Pro12Pro genotype and 14 with the Ala12Ala genotype were randomized to both a PUFA diet and a SAFA diet for 8 weeks in a crossover setting. Serum lipids and adipose tissue mRNA expression were measured during the diet intervention. At baseline, subjects with the Ala12Ala genotype had higher levels of HDL cholesterol and lower levels of LDL cholesterol, total triglycerides, and apolipoprotein B compared to those subjects with the Pro12Pro genotype (P < 0.05, FDR < 0.1). The Ala12Ala genotype also associated with higher mRNA expression of PPARG2, LPIN1, and SREBP-1c compared to participants with the Pro12Pro genotype (FDR < 0.001). On the other hand, PUFA diet resulted in lower levels of fasting glucose, total cholesterol, total triglycerides, and apolipoprotein B (P < 0.05, FDR < 0.1) but did not affect PPARG2 mRNA expression in adipose tissue. We conclude that individuals with the Pro12Pro genotype, with higher triglyceride levels at baseline, are more likely to benefit from the PUFA diet. However, the beneficial effects of dietary PUFA and the Ala12Ala genotype of PPARG on serum lipids are mediated through divergent mechanisms.
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Affiliation(s)
- Jussi Pihlajamäki
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70210, Kuopio, Finland. .,Department of Clinical Nutrition and Obesity Center, Kuopio University Hospital, Kuopio, Finland.
| | - Ursula Schwab
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70210, Kuopio, Finland.,Department of Clinical Nutrition and Obesity Center, Kuopio University Hospital, Kuopio, Finland
| | - Dorota Kaminska
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70210, Kuopio, Finland
| | - Jyrki Ågren
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Johanna Kuusisto
- Department of Medicine, Kuopio University Hospital, University of Eastern Finland, Kuopio, Finland
| | - Marjukka Kolehmainen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70210, Kuopio, Finland
| | - Jussi Paananen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70210, Kuopio, Finland
| | - Markku Laakso
- Department of Medicine, Kuopio University Hospital, University of Eastern Finland, Kuopio, Finland
| | - Matti Uusitupa
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70210, Kuopio, Finland.,Research Unit, Kuopio University Hospital, Kuopio, Finland
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18
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Abstract
OBJECTIVE Although elevated free fatty acid (FFA) levels in obesity have been considered to be of importance for insulin resistance, a recent meta-analysis suggested normal FFA levels in obese subjects. We investigated fasting circulating FFA and glycerol levels in a large cohort of non-obese and obese subjects. METHODS Subjects recruited for a study on obesity genetics were investigated in the morning after an overnight fast (n = 3,888). Serum FFA (n = 3,306), plasma glycerol (n = 3,776), and insulin sensitivity index (HOMA-IR,n = 3,469) were determined. Obesity was defined as BMI ≥ 30 kg/m 2 and insulin resistance as HOMA-IR ≥ 2.21. RESULTS In obese subjects, circulating FFA and glycerol levels were higher than in non-obese individuals (by 26% and 47%, respectively; both p < 0.0001). Similar results were obtained if only men, women or medication-free subjects were investigated. Insulin resistance and type 2 diabetes were associated with a further minor increase in FFA/glycerol among obese subjects. When comparing insulin-sensitive non-obese with insulin-sensitive or -resistant obese individuals, FFA and glycerol were 21–29% and 43–49% higher in obese individuals, respectively. CONCLUSION Circulating FFA and glycerol levels are markedly elevated in obesity but only marginally influenced by insulin resistance and type 2 diabetes. Whether these differences persist during diurnal variations in circulating FFA/glycerol, remains to be established
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Affiliation(s)
| | - Mikael Rydén
- *Prof. Dr. Dr. Mikael Rydén, C2-94, Karolinska Institutet, Department of Medicine (H7) and, Division of Endocrinology and Metabolism, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden,
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19
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Pinnick KE, Nicholson G, Manolopoulos KN, McQuaid SE, Valet P, Frayn KN, Denton N, Min JL, Zondervan KT, Fleckner J, McCarthy MI, Holmes CC, Karpe F. Distinct developmental profile of lower-body adipose tissue defines resistance against obesity-associated metabolic complications. Diabetes 2014; 63:3785-97. [PMID: 24947352 DOI: 10.2337/db14-0385] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Upper- and lower-body fat depots exhibit opposing associations with obesity-related metabolic disease. We defined the relationship between DEXA-quantified fat depots and diabetes/cardiovascular risk factors in a healthy population-based cohort (n = 3,399). Gynoid fat mass correlated negatively with insulin resistance after total fat mass adjustment, whereas the opposite was seen for abdominal fat. Paired transcriptomic analysis of gluteal subcutaneous adipose tissue (GSAT) and abdominal subcutaneous adipose tissue (ASAT) was performed across the BMI spectrum (n = 49; 21.4-45.5 kg/m(2)). In both depots, energy-generating metabolic genes were negatively associated and inflammatory genes were positively associated with obesity. However, associations were significantly weaker in GSAT. At the systemic level, arteriovenous release of the proinflammatory cytokine interleukin-6 (n = 34) was lower from GSAT than ASAT. Isolated preadipocytes retained a depot-specific transcriptional "memory" of embryonic developmental genes and exhibited differential promoter DNA methylation of selected genes (HOTAIR, TBX5) between GSAT and ASAT. Short hairpin RNA-mediated silencing identified TBX5 as a regulator of preadipocyte proliferation and adipogenic differentiation in ASAT. In conclusion, intrinsic differences in the expression of developmental genes in regional adipocytes provide a mechanistic basis for diversity in adipose tissue (AT) function. The less inflammatory nature of lower-body AT offers insight into the opposing metabolic disease risk associations between upper- and lower-body obesity.
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Affiliation(s)
- Katherine E Pinnick
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K.
| | - George Nicholson
- Department of Statistics, University of Oxford, Oxford, U.K. Medical Research Council Harwell, Harwell Science and Innovation Campus, Harwell, U.K
| | | | - Siobhán E McQuaid
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Philippe Valet
- Institut des Maladies Metaboliques et Cardiovasculaires, INSERM-Université Paul Sabatier, Toulouse, France
| | - Keith N Frayn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Nathan Denton
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Josine L Min
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, U.K
| | - Krina T Zondervan
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, U.K
| | - Jan Fleckner
- Novo Nordisk A/S, Novo Nordisk Park, Gentofte, Denmark
| | | | - Mark I McCarthy
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, U.K. National Institute for Health Research, Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, U.K
| | - Chris C Holmes
- Department of Statistics, University of Oxford, Oxford, U.K
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K. National Institute for Health Research, Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, U.K
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20
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Li Q, Chen R, Bie L, Zhao D, Huang C, Hong J. Association of the variants in the PPARG gene and serum lipid levels: a meta-analysis of 74 studies. J Cell Mol Med 2014; 19:198-209. [PMID: 25265984 PMCID: PMC4288363 DOI: 10.1111/jcmm.12417] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/09/2014] [Indexed: 01/03/2023] Open
Abstract
Considerable studies have been carried out to investigate the relationship between the polymorphisms of PPARG (Pro12Ala, C161T and C1431T) and serum lipid levels, but the results were inconclusive. Hence, we conducted a meta-analysis to clarify the association. MEDLINE, EMBASE and the Cochrane Library databases were searched systematically. The subgroup analysis was performed based on ethnicity. Seventy-four studies with 54,953 subjects were included in this meta-analysis. In Pro12Ala, the group with the ‘PP’ (C/C genotype) genotype group had lower levels of total cholesterol (TC) (mean difference, MD: −0.02, P < 0.00001; I2 = 28%), low-density lipoprotein cholesterol (LDL-C) (MD: −0.02, P < 0.00001; I2 = 30%) and higher levels of triglyceride (TG) (MD: 0.06, P < 0.00001; I2 = 30%) than the combined ‘PA+AA’ (PA = C/G genotype, AA = G/G genotype) genotype group in Asian population, and the group with the ‘PP’ genotype had higher levels of TG (MD: 0.07, P < 0.02; I2 = 67%) than the combined ‘PA+AA’ genotype group in non-Asian population. No statistically significant differences in the levels of TC, TG, high-density lipoprotein cholesterol, LDL-C were detected between different genotypes in C161T(Asian or non-Asian) and C1431T(Asian) polymorphisms. This meta-analysis was a renewed and confirmed study to assess the association between PPARG polymorphisms and serum lipid levels in Asian and non-Asian populations. There is a prominent association between Pro12Ala polymorphism and the levels of TC, LDL-C and TG in Asian population. No statistically significant differences in serum lipid levels were detected between different genotypes in C161T and C1431T polymorphisms.
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Affiliation(s)
- Qing Li
- Department of Internal Medicine, Affiliated Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai, China
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21
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McNeil CA, Pramfalk C, Humphreys SM, Hodson L. The storage stability and concentration of acetoacetate differs between blood fractions. Clin Chim Acta 2014; 433:278-83. [PMID: 24721643 DOI: 10.1016/j.cca.2014.03.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/27/2014] [Accepted: 03/27/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND Plasma concentrations of 3-hydroxybutyrate (3HB) are measured more often than acetoacetate (AcAc) which may be due to the reported storage instability of AcAc. The aims of the study were to compare the storage stability of AcAc in different blood fractions over time (90days) when stored at -80°C and to determine the postprandial concentration of AcAc in whole blood, plasma and red blood cells. METHODS Blood was collected from fasting subjects (n=5): whole blood, plasma and red blood cells were isolated and deproteinised in perchloric acid, and supernatants were stored at -80°C until analysis. Postprandial concentrations of AcAc in whole blood, plasma and red blood cells were determined at regular intervals over 420min, after subjects (n=23) had consumed a mixed test meal. RESULTS Storing deproteinised plasma at -80°C resulted in no significant change in AcAc concentration over 60days. In contrast, whole blood AcAc concentrations significantly decreased by 51% (p=0.018) within 30days. The concentration of AcAc in fasting and postprandial plasma was notably higher than that of whole blood and red blood cells. DISCUSSION Our data demonstrates that plasma for AcAc analysis can be stored for longer than previously suggested provided that plasma is deproteinised and stored at -80°C.
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Affiliation(s)
- Catriona A McNeil
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LE, UK
| | - Camilla Pramfalk
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LE, UK
| | - Sandy M Humphreys
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LE, UK
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LE, UK.
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22
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Lower resting and total energy expenditure in postmenopausal compared with premenopausal women matched for abdominal obesity. J Nutr Sci 2014; 3:e3. [PMID: 25191611 PMCID: PMC4153012 DOI: 10.1017/jns.2013.38] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 11/15/2013] [Accepted: 12/02/2013] [Indexed: 02/05/2023] Open
Abstract
The menopause is accompanied by increased risk of obesity, altered body fat distribution and decreased skeletal muscle mass. The resulting decrease in RMR should be accompanied by a compensatory change in energy balance to avoid weight gain. We aimed to investigate habitual energy intake and expenditure in pre- and postmenopausal women matched for abdominal obesity. We recruited fifty-one healthy Caucasian women, BMI > 18·5 and <35 kg/m(2), aged 35-45 years (premenopausal, n 26) and 55-65 years (postmenopausal, n 25). Energy intake was measured using 3 d diet diaries and dietary fat quality assessed using adipose tissue fatty acid biomarkers. RMR was measured using indirect calorimetry, and total energy expenditure (TEE) and activity energy expenditure using a combined accelerometer and heart rate monitor. Postmenopausal women had lower RMR and TEE and spent significantly less time undertaking moderate exercise than premenopausal women. Postmenopausal women had a tendency for a lower energy intake, and a similar macronutrient intake but a significantly lower adipose tissue n-6:n-3 ratio (24·6 (se 1·6) v. 37·7 (se 3·1); P < 0·001). The main lifestyle determinant of bone mineral density (which was significantly lower in postmenopausal women) was TEE for premenopausal women, and dietary n-6:n-3 ratio for postmenopausal women. The present results suggest that weight maintenance is achieved in the post- compared with premenopausal status through a combination of reduced energy intake and reduced TEE in a regimen that compromises micronutrient intake and has a negative impact on lean tissue mass. However, lower n-6:n-3 fatty acid intake in postmenopausal women is associated with greater bone mineral density.
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Marinou K, Hodson L, Vasan SK, Fielding BA, Banerjee R, Brismar K, Koutsilieris M, Clark A, Neville MJ, Karpe F. Structural and functional properties of deep abdominal subcutaneous adipose tissue explain its association with insulin resistance and cardiovascular risk in men. Diabetes Care 2014; 37:821-9. [PMID: 24186879 DOI: 10.2337/dc13-1353] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Fat distribution is an important variable explaining metabolic heterogeneity of obesity. Abdominal subcutaneous adipose tissue (SAT) is divided by the Scarpa's fascia into a deep subcutaneous adipose tissue (dSAT) and a superficial subcutaneous adipose tissue (sSAT) layer. This study sought to characterize functional differences between the two SAT layers to explore their relative contribution to metabolic traits and cardiovascular risk (CVR) profile. RESEARCH DESIGN AND METHODS We recruited 371 Caucasians consecutively from a local random, population-based screening project in Oxford and 25 Asian Indians from the local community. The depth of the SAT layers was determined by ultrasound (US), and adipose tissue (AT) biopsies were performed under US guidance in a subgroup of 43 Caucasians. Visceral adipose tissue (VAT) mass was quantified by dual-energy X-ray absorptiometry scan. RESULTS Male adiposity in both ethnic groups was characterized by a disproportionate expansion of dSAT, which was strongly correlated with VAT mass. dSAT depth was a strong predictor of global insulin resistance (IR; homeostatic model assessment of IR), liver-specific IR (insulin-like growth factor binding protein-1), and Framingham risk score independently of other measures of adiposity in men. Moreover, dSAT had higher expression of proinflammatory, lipogenic, and lipolytic genes and contained higher proportions of saturated fatty acids. There was increased proportion of small adipocytes in dSAT. CONCLUSIONS SAT is heterogeneous; dSAT expands disproportionally more than sSAT with increasing obesity in Caucasian males (confirmed also in Asian Indians). Its expansion is related to increased CVR independent of other adiposity measures, and it has biological properties suggestive of higher metabolic activity contributing to global IR.
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Sell H, Blüher M, Klöting N, Schlich R, Willems M, Ruppe F, Knoefel WT, Dietrich A, Fielding BA, Arner P, Frayn KN, Eckel J. Adipose dipeptidyl peptidase-4 and obesity: correlation with insulin resistance and depot-specific release from adipose tissue in vivo and in vitro. Diabetes Care 2013; 36:4083-90. [PMID: 24130353 PMCID: PMC3836153 DOI: 10.2337/dc13-0496] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To study expression of the recently identified adipokine dipeptidyl peptidase-4 (DPP4) in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) of patients with various BMIs and insulin sensitivities, as well as to assess circulating DPP4 in relation to obesity and insulin sensitivity. RESEARCH DESIGN AND METHODS DPP4 expression was measured in SAT and VAT from 196 subjects with a wide range of BMIs and insulin sensitivities. DPP4 release was measured ex vivo in paired biopsies from SAT and VAT as well as in vivo from SAT of lean and obese patients. Circulating DPP4 was measured in insulin-sensitive and insulin-resistant BMI-matched obese patients. RESULTS DPP4 expression was positively correlated with BMI in both SAT and VAT, with VAT consistently displaying higher expression than SAT. Ex vivo release of DPP4 from adipose tissue explants was higher in VAT than in SAT in both lean and obese patients, with obese patients displaying higher DPP4 release than lean controls. Net release of DPP4 from adipose tissue was also demonstrated in vivo with greater release in obese subjects than in lean subjects and in women than in men. Insulin-sensitive obese patients had significantly lower circulating DPP4 than did obesity-matched insulin-resistant patients. In this experiment, DPP4 positively correlated with the amount of VAT, adipocyte size, and adipose tissue inflammation. CONCLUSIONS DPP4, a novel adipokine, has a higher release from VAT that is particularly pronounced in obese and insulin-resistant patients. Our data suggest that DPP4 may be a marker for visceral obesity, insulin resistance, and the metabolic syndrome.
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Hodson L, Neville M, Chong MFF, Rogers I, Huda SS, Freeman DJ, Frayn KN, Fielding BA. Micro-techniques for analysis of human adipose tissue fatty acid composition in dietary studies. Nutr Metab Cardiovasc Dis 2013; 23:1128-1133. [PMID: 23228218 DOI: 10.1016/j.numecd.2012.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/29/2012] [Accepted: 11/03/2012] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND AIMS Adipose tissue (AT) fatty acid (FA) composition is considered to be the gold standard long-term biomarker of dietary fatty acid intake. Typically this measurement is made directly from samples collected via large-needle-biopsy or incision. However, with growing interest in the role of AT in relation to health, ideally the fatty acid composition would be analysed along with other measurements, such as gene expression or histology, on a single AT sample. Here we assess alternative ways of obtaining AT for measuring FA composition, in some cases in conjunction with other measurements. METHODS AND RESULTS The FA composition of tissue obtained via different methods was compared to that of tissue collected via large-needle or surgical biopsy. Fatty acid composition was not significantly different in AT collected by small-needle mini-biopsy (n = 10), from an RNA 'lipid layer' (obtained during RNA extraction, 2 sites, n = 6 for each), or from cryosectioned tissue prepared for histology (n = 10). We also assessed the usefulness of the composition of plasma NEFA as a surrogate marker of subcutaneous AT (n = 58-80). Most FAs in plasma NEFA correlated strongly with those in AT (P < 0.05). CONCLUSION It is feasible to measure the FA composition of AT on very small amounts of tissue. Additionally, it is possible to measure FA composition on the lipid rich 'by-product' of AT samples undergoing RNA extraction for gene expression. Samples sectioned for histology are also suitable. This provides further opportunities for multidisciplinary collaborations that may lead to a better application of dietary biomarkers.
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Affiliation(s)
- L Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Oxford OX3 7LE, UK.
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26
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Pereira AC, Oliveira R, Castro AC, Fernandes R. Does Pro(12)Ala Polymorphism Enhance the Physiological Role of PPARγ2? PPAR Res 2013; 2013:401274. [PMID: 23983677 PMCID: PMC3747383 DOI: 10.1155/2013/401274] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/29/2013] [Indexed: 11/28/2022] Open
Abstract
Obesity and type 2 diabetes mellitus (T2D) are two major public health problems that have motivated the scientific community to investigate the high contribution of genetic factors to these disorders. The peroxisome proliferator activated by gamma 2 (PPARγ2) plays an important role in the lipid metabolism. Since PPARγ2 is expressed mainly in adipose tissue, a moderate reduction of its activity influences the sensitivity to insulin, diabetes, and other metabolic parameters. The present study aims to contribute to the elucidation of the impact of the Pro(12)Ala polymorphism associated with T2D and obesity through a meta-analysis study of the literature that included approximately 11500 individuals, from which 3870 were obese and 7625 were diabetic. Statistical evidence supports protective effect in T2D of polymorphism Pro(12)Ala of PPARγ2 (OR = 0.702 with 95% CI: 0.622; 0.791, P < 0.01). Conversely the same polymorphism Pro(12)Ala of PPARγ2 seems to favor obesity since 1.196 more chance than nonobese was found (OR = 1.196 with 95% CI: 1.009; 1.417, P < 0.004). Our results suggest that Pro(12)Ala polymorphism enhances both adipogenic and antidiabetogenic physiological role of PPARγ. Does Pro(12)Ala polymorphism represent an evolutionary step towards the stabilization of the molecular function of PPARγ transcription factor signaling pathway?
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Affiliation(s)
- A. C. Pereira
- Unit of Molecular Mechanisms of Disease (CISA) and Chemical and Biomolecular Sciences, School of Allied Health Sciences, Polytechnic Institute of Porto (ESTSP-IPP), Portugal
- Center of Pharmacology and Chemical Biopathology (U38-FCT), Medical Faculty, University of Porto, Portugal
| | - R. Oliveira
- Center for Research in Health Technologies and Information Systems (CINTESIS), Medical Faculty, University of Porto, Portugal
- Biomathematics, Biostatistics and Bioinformatics, ESTSP-IPP, Porto, Portugal
| | - A. C. Castro
- Unit of Molecular Mechanisms of Disease (CISA) and Chemical and Biomolecular Sciences, School of Allied Health Sciences, Polytechnic Institute of Porto (ESTSP-IPP), Portugal
| | - R. Fernandes
- Unit of Molecular Mechanisms of Disease (CISA) and Chemical and Biomolecular Sciences, School of Allied Health Sciences, Polytechnic Institute of Porto (ESTSP-IPP), Portugal
- Center of Pharmacology and Chemical Biopathology (U38-FCT), Medical Faculty, University of Porto, Portugal
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Abstract
Adipose tissue (AT) hypoxia has been proposed as the cause of obesity-related AT dysfunction, moving the tissue toward a proinflammatory phenotype. In humans, AT oxygenation has been assessed by expression of hypoxia-sensitive genes or direct assessment of O₂ tension; the obvious read out of hypoxia, effects on intermediary metabolism, has not been investigated. We used tissue-specific venous catheterization of subcutaneous abdominal AT in humans to investigate oxygen-related metabolic processes, searching for metabolic signatures relating to hypoxia in obesity. O₂ delivery to AT was reduced in obesity (P < 0.05). However, O₂ consumption was low (<30% of resting forearm skeletal muscle [SM], P < 0.001); this was not related to obesity. AT primarily oxidized glucose, as demonstrated by a respiratory quotient close to 1.0 (higher than SM, P < 0.05). AT was a net producer of lactate, but there was an inverse relationship in venous outflow between lactate-to-pyruvate ratio (a marker of cytosolic redox state) and BMI, suggesting that AT is glycolytic but obese AT is not hypoxic. Although delivery of O₂ to the obese AT is reduced, O₂ consumption is low, and metabolic signatures of human AT do not support the notion of a hypoxic state in obesity.
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Affiliation(s)
- Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, UK.
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28
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Magné J, Aminoff A, Perman Sundelin J, Mannila MN, Gustafsson P, Hultenby K, Wernerson A, Bauer G, Listenberger L, Neville MJ, Karpe F, Borén J, Ehrenborg E. The minor allele of the missense polymorphism Ser251Pro in perilipin 2 (PLIN2) disrupts an α-helix, affects lipolysis, and is associated with reduced plasma triglyceride concentration in humans. FASEB J 2013; 27:3090-9. [PMID: 23603836 DOI: 10.1096/fj.13-228759] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Perilipin 2 (PLIN2) is the most abundant lipid droplet (LD)-associated protein in nonadipose tissue, and its expression correlates with intracellular lipid accumulation. Here we identified a missense polymorphism, Ser251Pro, that has major effect on protein structure and function, along with an influence on human plasma triglyceride concentration. The evolutionarily conserved Ser251Pro polymorphism was identified with the ClustalW program. Structure modeling using 3D-JigSaw and the Chimera package revealed that the Pro251 allele disrupts a predicted α-helix in PLIN2. Analyses of macrophages from individuals carrying Ser251Pro variants and human embryonic kidney 293 (HEK293) cells stably transfected with either of the alleles demonstrated that the Pro251 variant causes increased lipid accumulation and decreased lipolysis. Analysis of LD size distribution in stably transfected cells showed that the minor Pro251 allele resulted in an increased number of small LDs per cell and increased perilipin 3 protein expression levels as compared with cells carrying the major Ser251 allele. Genotyping of 2113 individuals indicated that the Pro251 variant is associated with decreased plasma triglyceride and very low-density lipoprotein concentrations. Altogether, these data provide the first evidence of a polymorphism in PLIN2 that affects PLIN2 function and may influence the development of metabolic and cardiovascular diseases.
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Affiliation(s)
- Joëlle Magné
- Atherosclerosis Research Unit, Department of Medicine, Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
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29
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Drong AW, Nicholson G, Hedman ÅK, Meduri E, Grundberg E, Small KS, Shin SY, Bell JT, Karpe F, Soranzo N, Spector TD, McCarthy MI, Deloukas P, Rantalainen M, Lindgren CM. The presence of methylation quantitative trait loci indicates a direct genetic influence on the level of DNA methylation in adipose tissue. PLoS One 2013; 8:e55923. [PMID: 23431366 PMCID: PMC3576415 DOI: 10.1371/journal.pone.0055923] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 01/03/2013] [Indexed: 11/19/2022] Open
Abstract
Genetic variants that associate with DNA methylation at CpG sites (methylation quantitative trait loci, meQTLs) offer a potential biological mechanism of action for disease associated SNPs. We investigated whether meQTLs exist in abdominal subcutaneous adipose tissue (SAT) and if CpG methylation associates with metabolic syndrome (MetSyn) phenotypes. We profiled 27,718 genomic regions in abdominal SAT samples of 38 unrelated individuals using differential methylation hybridization (DMH) together with genotypes at 5,227,243 SNPs and expression of 17,209 mRNA transcripts. Validation and replication of significant meQTLs was pursued in an independent cohort of 181 female twins. We find that, at 5% false discovery rate, methylation levels of 149 DMH regions associate with at least one SNP in a ±500 kilobase cis-region in our primary study. We sought to validate 19 of these in the replication study and find that five of these significantly associate with the corresponding meQTL SNPs from the primary study. We find that none of the 149 meQTL top SNPs is a significant expression quantitative trait locus in our expression data, but we observed association between expression levels of two mRNA transcripts and cis-methylation status. Our results indicate that DNA CpG methylation in abdominal SAT is partly under genetic control. This study provides a starting point for future investigations of DNA methylation in adipose tissue.
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Affiliation(s)
- Alexander W. Drong
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - George Nicholson
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Åsa K. Hedman
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Eshwar Meduri
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Elin Grundberg
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
- Department of Twin Research, King's College London, London, United Kingdom
| | - Kerrin S. Small
- Department of Twin Research, King's College London, London, United Kingdom
| | - So-Youn Shin
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Jordana T. Bell
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Department of Twin Research, King's College London, London, United Kingdom
| | - Fredrik Karpe
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, United Kingdom
| | - Nicole Soranzo
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Tim D. Spector
- Department of Twin Research, King's College London, London, United Kingdom
| | - Mark I. McCarthy
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, United Kingdom
| | - Panos Deloukas
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | | | - Cecilia M. Lindgren
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
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McHugh SM, Roman S, Davis B, Koch A, Pickett AM, Richardson JC, Miller SR, Wetten S, Cox CJ, Karpe F, Todd JA, Bullmore ET. Effects of genetic variation in the P2RX7 gene on pharmacodynamics of a P2X(7) receptor antagonist: a prospective genotyping approach. Br J Clin Pharmacol 2012; 74:376-80. [PMID: 22295949 DOI: 10.1111/j.1365-2125.2012.04200.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIMS To investigate the effects of two single nucleotide polymorphisms (SNPs) in the human P2X₇ receptor gene (P2RX7)--1068G>A (A348T) and 1513A>C (E496A)--on P2X₇ receptor function, using a specific receptor antagonist (GSK1370319A) and prospective genetic stratification. METHODS Lipopolysaccharide- and ATP-stimulated interleukin-1β production was determined in the presence or absence of GSK1370319A in blood culture from 32 prospectively genotyped subjects. RESULTS There was approximately 6.7-fold difference (P < 0.0001) in IC₅₀ for inhibition of ATP-stimulated interleukin-1β release by GSK1370319A between individuals with the homozygous gain--(1068A) and loss-of-function (1513C) genotypes (expressing the 348T, 496E and 348A, 496A alleles, respectively). CONCLUSIONS Leukocyte P2X₇ receptors had significantly altered pharmacodynamic responses to a specific antagonist (GSK1370319A), directly related to SNP genotype.
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Affiliation(s)
- Simon M McHugh
- GSK Clinical Unit Cambridge-CUC, Addenbrooke's Hospital, Box 128, Hills Road, Cambridge CB2 0GG, UK.
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31
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Manolopoulos KN, Karpe F, Frayn KN. Marked resistance of femoral adipose tissue blood flow and lipolysis to adrenaline in vivo. Diabetologia 2012; 55:3029-37. [PMID: 22898765 DOI: 10.1007/s00125-012-2676-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/05/2012] [Indexed: 01/14/2023]
Abstract
AIMS/HYPOTHESIS Fatty acid entrapment in femoral adipose tissue has been proposed to prevent ectopic fat deposition and visceral fat accumulation, resulting in protection from insulin resistance. Our objective was to test the hypothesis of femoral, compared with abdominal, adipose tissue resistance to adrenergic stimulation in vivo as a possible mechanism. METHODS Regional fatty acid trafficking, along with the measurement of adipose tissue blood flow (ATBF) with (133)Xe washout, was studied with the arteriovenous difference technique and stable isotope tracers in healthy volunteers. Adrenergic agonists (isoprenaline, adrenaline [epinephrine]) were infused either locally by microinfusion or systemically. Local microinfusion of adrenoceptor antagonists (propranolol, phentolamine) was used to characterise specific adrenoceptor subtype effects in vivo. RESULTS Femoral adipose tissue NEFA release and ATBF were lower during adrenaline stimulation than in abdominal tissue (p < 0.001). Mechanistically, femoral adipose tissue displayed a dominant α-adrenergic response during adrenaline stimulation. The α-adrenoceptor blocker, phentolamine, resulted in the 'disinhibition' of the femoral ATBF response to adrenaline (p < 0.001). CONCLUSIONS/INTERPRETATION Fatty acids, once stored in femoral adipose tissue, are not readily released upon adrenergic stimulation. Femoral adipose tissue resistance to adrenaline may contribute to the prevention of ectopic fatty acid deposition.
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Affiliation(s)
- K N Manolopoulos
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, UK.
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Robertson MD, Wright JW, Loizon E, Debard C, Vidal H, Shojaee-Moradie F, Russell-Jones D, Umpleby AM. Insulin-sensitizing effects on muscle and adipose tissue after dietary fiber intake in men and women with metabolic syndrome. J Clin Endocrinol Metab 2012; 97:3326-32. [PMID: 22745235 DOI: 10.1210/jc.2012-1513] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
CONTEXT Dietary fibers have been associated with a reduced incidence of type 2 diabetes mellitus in epidemiological studies; however, the precise mechanisms are unknown. OBJECTIVE The objective of the study was to evaluate the efficacy and site of action of an insoluble dietary fiber derived from maize (HAM-RS2) in improving insulin resistance in subjects at increased risk of type 2 diabetes mellitus. DESIGN This study was a randomized, controlled crossover, dietary intervention study. SETTING The study was conducted at the Centre for Diabetes, Endocrinology, and Research, Royal Surrey County Hospital, Guildford, United Kingdom. PARTICIPANTS Fifteen men and women with insulin resistance participated in the study. INTERVENTION The intervention included 40 g/d HAM-RS2 compared with a matched placebo for 8 wk. MAIN OUTCOME MEASURES After each supplement, participants underwent a two-step hyperinsulinemic-euglycemic clamp study with the addition of glucose tracers; a meal tolerance test; arteriovenous sampling across forearm muscle tissue; and a sc adipose tissue biopsy for assessment of gene expression. RESULTS There was enhanced uptake of glucose into the forearm muscle measured by arteriovenous sampling (65 ± 15% increase after resistant starch; P < 0.001). Adipose tissue function was also affected, with enhanced fatty acid suppression after HAM-RS2 treatment and an increase in gene expression for hormone sensitive lipase (P = 0.005), perilipin (P = 0.011), lipoprotein lipase (P = 0.014), and adipose triglyceride lipase (P = 0.03) in biopsy samples. There was no effect on the insulin sensitivity of hepatic glucose production or plasma lipids after HAM-RS2. CONCLUSION HAM-RS2 improved peripheral but not hepatic insulin resistance and requires further study as an intervention in patients with or at risk for type 2 diabetes.
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Affiliation(s)
- M Denise Robertson
- Department of Diabetes and Metabolic Medicine, Postgraduate Medical School, University of Surrey, Guildford GU2 7WG, United Kingdom.
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Sotornik R, Brassard P, Martin E, Yale P, Carpentier AC, Ardilouze JL. Update on adipose tissue blood flow regulation. Am J Physiol Endocrinol Metab 2012; 302:E1157-70. [PMID: 22318953 DOI: 10.1152/ajpendo.00351.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
According to Fick's principle, any metabolic or hormonal exchange through a given tissue depends on the product of the blood flow to that tissue and the arteriovenous difference. The proper function of adipose tissue relies on adequate adipose tissue blood flow (ATBF), which determines the influx and efflux of metabolites as well as regulatory endocrine signals. Adequate functioning of adipose tissue in intermediary metabolism requires finely tuned perfusion. Because metabolic and vascular processes are so tightly interconnected, any disruption in one will necessarily impact the other. Although altered ATBF is one consequence of expanding fat tissue, it may also aggravate the negative impacts of obesity on the body's metabolic milieu. This review attempts to summarize the current state of knowledge on adipose tissue vascular bed behavior under physiological conditions and the various factors that contribute to its regulation as well as the possible participation of altered ATBF in the pathophysiology of metabolic syndrome.
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Affiliation(s)
- Richard Sotornik
- Diabetes and Metabolism Research Group, Division of Endocrinology, Department of Medicine, Centre Hospitalier, Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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Influence of different CLA isomers on insulin resistance and adipocytokines in pre-diabetic, middle-aged men with PPARγ2 Pro12Ala polymorphism. GENES AND NUTRITION 2012; 7:499-509. [PMID: 22399314 DOI: 10.1007/s12263-012-0289-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 02/17/2012] [Indexed: 12/13/2022]
Abstract
Conjugated linoleic acids (CLAs) are natural PPARγ ligands, which showed conflicting effects on metabolism in humans. We examined metabolic effects of different isomers of CLA in subjects with PPARγ2 Pro12Ala polymorphisms. A total of 35 men underwent four intervention periods in a crossover study design: subjects with either genotypes received c9, t11 CLA or t10, c12 CLA, a commercially available 1:1 mix of both isomers or reference oil (linoleic acid (LA)). Adipocytokines, insulin, glucose and triglycerides were assessed in the fasting state and after a standardized mixed meal. Across all genotypes, there was a significant (p = 0.025) CLA treatment effect upon postprandial (pp) HOMA-IR values, with c9, t11 CLA and CLA isomer mix improving, but t10, c12 CLA isomer worsening. In Ala12Ala subjects, the t10, c12 isomer caused weight gain (p = 0.03) and tended to increase postprandial insulin levels (p = 0.05). In Pro12Pro subjects, t10, c12 resulted in reduction in waist circumference (p = 0.03). The comparison of the different genotype groups revealed statistically different changes in fasting and postprandial insulin, HOMA-IR and leptin after intervention. c9, t11 CLA and the commercial CLA mix showed beneficial effects on insulin sensitivity compared with LA, while t10, c12 CLA adversely affects body weight and insulin sensitivity in different PPAR genotypes. CLA isomers have different effects on metabolism in Ala and Pro carriers.
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Min JL, Nicholson G, Halgrimsdottir I, Almstrup K, Petri A, Barrett A, Travers M, Rayner NW, Mägi R, Pettersson FH, Broxholme J, Neville MJ, Wills QF, Cheeseman J, Allen M, Holmes CC, Spector TD, Fleckner J, McCarthy MI, Karpe F, Lindgren CM, Zondervan KT. Coexpression network analysis in abdominal and gluteal adipose tissue reveals regulatory genetic loci for metabolic syndrome and related phenotypes. PLoS Genet 2012; 8:e1002505. [PMID: 22383892 PMCID: PMC3285582 DOI: 10.1371/journal.pgen.1002505] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 12/11/2011] [Indexed: 01/11/2023] Open
Abstract
Metabolic Syndrome (MetS) is highly prevalent and has considerable public health impact, but its underlying genetic factors remain elusive. To identify gene networks involved in MetS, we conducted whole-genome expression and genotype profiling on abdominal (ABD) and gluteal (GLU) adipose tissue, and whole blood (WB), from 29 MetS cases and 44 controls. Co-expression network analysis for each tissue independently identified nine, six, and zero MetS–associated modules of coexpressed genes in ABD, GLU, and WB, respectively. Of 8,992 probesets expressed in ABD or GLU, 685 (7.6%) were expressed in ABD and 51 (0.6%) in GLU only. Differential eigengene network analysis of 8,256 shared probesets detected 22 shared modules with high preservation across adipose depots (DABD-GLU = 0.89), seven of which were associated with MetS (FDR P<0.01). The strongest associated module, significantly enriched for immune response–related processes, contained 94/620 (15%) genes with inter-depot differences. In an independent cohort of 145/141 twins with ABD and WB longitudinal expression data, median variability in ABD due to familiality was greater for MetS–associated versus un-associated modules (ABD: 0.48 versus 0.18, P = 0.08; GLU: 0.54 versus 0.20, P = 7.8×10−4). Cis-eQTL analysis of probesets associated with MetS (FDR P<0.01) and/or inter-depot differences (FDR P<0.01) provided evidence for 32 eQTLs. Corresponding eSNPs were tested for association with MetS–related phenotypes in two GWAS of >100,000 individuals; rs10282458, affecting expression of RARRES2 (encoding chemerin), was associated with body mass index (BMI) (P = 6.0×10−4); and rs2395185, affecting inter-depot differences of HLA-DRB1 expression, was associated with high-density lipoprotein (P = 8.7×10−4) and BMI–adjusted waist-to-hip ratio (P = 2.4×10−4). Since many genes and their interactions influence complex traits such as MetS, integrated analysis of genotypes and coexpression networks across multiple tissues relevant to clinical traits is an efficient strategy to identify novel associations. Metabolic Syndrome (MetS) is a highly prevalent disorder with considerable public health concern, but its underlying genetic factors remain elusive. Given that most cellular components exert their functions through interactions with other cellular components, even the largest of genome-wide association (GWA) studies may often not detect their effects, nor necessarily provide insight into the complex molecular mechanisms of the disease. Rather than focusing on individual genes, the analysis of coexpression networks can be used for finding clusters (modules) of correlated expression levels across samples. In this study, we used a gene network–based approach for integrating clinical MetS, genotypic, and gene expression data from abdominal and gluteal adipose tissue and whole blood. We identified modules of genes related to MetS significantly enriched for immune response and oxidative phosphorylation pathways. We tested SNPs for association with MetS–associated expression (eSNPs), and tested prioritised eSNPs for association with MetS–related phenotypes in two large-scale GWA datasets. We identified two loci, neither of which had reached genome-wide significance levels in GWAs, associated with expression levels of RARRES2 and HLA-DRB1 and with MetS–related phenotypes, demonstrating that the integrated analysis of genotype and expression data from relevant multiple tissues can identify novel associations with complex traits such as MetS.
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Affiliation(s)
- Josine L. Min
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail: (JLM); (KTZ)
| | - George Nicholson
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | | | - Kristian Almstrup
- Department of Molecular Genetics, Novo Nordisk A/S, Maaloev, Denmark
| | - Andreas Petri
- Department of Molecular Genetics, Novo Nordisk A/S, Maaloev, Denmark
| | - Amy Barrett
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford, United Kingdom
| | - Mary Travers
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford, United Kingdom
| | - Nigel W. Rayner
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford, United Kingdom
| | - Reedik Mägi
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Estonian Genome Center, University of Tartu, Tartu, Estonia
| | - Fredrik H. Pettersson
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - John Broxholme
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Matt J. Neville
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, ORH Trust, Churchill Hospital, Oxford, United Kingdom
| | - Quin F. Wills
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Jane Cheeseman
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford, United Kingdom
| | | | | | - Maxine Allen
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford, United Kingdom
| | - Chris C. Holmes
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Tim D. Spector
- Twin Research Unit, King's College London, London, United Kingdom
| | - Jan Fleckner
- Department of Molecular Genetics, Novo Nordisk A/S, Maaloev, Denmark
| | - Mark I. McCarthy
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, ORH Trust, Churchill Hospital, Oxford, United Kingdom
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, ORH Trust, Churchill Hospital, Oxford, United Kingdom
| | - Cecilia M. Lindgren
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Krina T. Zondervan
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail: (JLM); (KTZ)
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Frayn KN, Humphreys SM. Metabolic characteristics of human subcutaneous abdominal adipose tissue after overnight fast. Am J Physiol Endocrinol Metab 2012; 302:E468-75. [PMID: 22167523 PMCID: PMC3287351 DOI: 10.1152/ajpendo.00527.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Subcutaneous abdominal adipose tissue is one of the largest fat depots and contributes the major proportion of circulating nonesterified fatty acids (NEFA). Little is known about aspects of human adipose tissue metabolism in vivo other than lipolysis. Here we collated data from 331 experiments in 255 healthy volunteers over a 23-year period, in which subcutaneous abdominal adipose tissue metabolism was studied by measurements of arterio-venous differences after an overnight fast. NEFA and glycerol were released in a ratio of 2.7:1, different (P < 0.001) from the value of 3.0 that would indicate no fatty acid re-esterification. Fatty acid re-esterification was 10.2 ± 1.4%. Extraction of triacylglycerol (TG) (fractional extraction 5.7 ± 0.4%) indicated intravascular lipolysis by lipoprotein lipase, and this contributed 21 ± 3% of the glycerol released. Glucose uptake (fractional extraction 2.6 ± 0.3%) was partitioned around 20-25% for provision of glycerol 3-phosphate and 30% into lactate production. There was release of lactate and pyruvate, with extraction of the ketone bodies 3-hydroxybutyrate and acetoacetate, although these were small numerically compared with TG and glucose uptake. NEFA release (expressed per 100 g tissue) correlated inversely with measures of fat mass (e.g., with BMI, r(s) = -0.24, P < 0.001). We examined within-person variability. Systemic NEFA concentrations, NEFA release, fatty acid re-esterification, and adipose tissue blood flow were all more consistent within than between individuals. This picture of human adipose tissue metabolism in the fasted state should contribute to a greater understanding of adipose tissue physiology and pathophysiology.
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Affiliation(s)
- Keith N Frayn
- Oxford Centre for Diabetes, Endocrinology & Metabolism, Churchill Hospital, Oxford OX3 7LJ, UK.
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Wang H, Dong S, Xu H, Qian J, Yang J. Genetic variants in FTO associated with metabolic syndrome: a meta- and gene-based analysis. Mol Biol Rep 2011; 39:5691-8. [PMID: 22189543 DOI: 10.1007/s11033-011-1377-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Accepted: 12/13/2011] [Indexed: 01/19/2023]
Abstract
The objective of this study was to examine the effect of genetic variants in fat mass and obesity associated (FTO) gene on metabolic syndrome (MetS). A systematic literature search was performed and random-effects meta-analysis was used to evaluate genetic variants in FTO with MetS. A gene-based analysis was conducted to investigate the cumulative effects of genetic polymorphisms in FTO. A total of 18 studies from 13 published papers were included in our analysis. Random-effects meta-analysis yielded an estimated odds ratio of 1.19 (95% CI 1.12-1.27; P = 1.38 × 10(-7)) for rs9939609, 1.19 (95% CI 1.05-1.35; P = 0.008) for rs8050136, and 1.89 (95% CI 1.20-2.96; P = 0.006) for rs1421085. The gene-based analysis indicated that FTO is strongly associated with MetS (P < 10(-5)). This association remains after excluding rs9939609, a SNP that was frequently reported to have strong association with obesity and MetS. In this study, we concluded that the FTO gene may play a critical role in leading to MetS. Targeting this gene may provide novel therapeutic strategies for the prevention and treatment of metabolic syndrome.
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Affiliation(s)
- Haina Wang
- College of Pharmaceutical Sciences, Shandong University, Jinan, Shandong, China
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Rantalainen M, Herrera BM, Nicholson G, Bowden R, Wills QF, Min JL, Neville MJ, Barrett A, Allen M, Rayner NW, Fleckner J, McCarthy MI, Zondervan KT, Karpe F, Holmes CC, Lindgren CM. MicroRNA expression in abdominal and gluteal adipose tissue is associated with mRNA expression levels and partly genetically driven. PLoS One 2011; 6:e27338. [PMID: 22102887 PMCID: PMC3216936 DOI: 10.1371/journal.pone.0027338] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 10/14/2011] [Indexed: 12/24/2022] Open
Abstract
To understand how miRNAs contribute to the molecular phenotype of adipose tissues and related traits, we performed global miRNA expression profiling in subcutaneous abdominal and gluteal adipose tissue of 70 human subjects and characterised which miRNAs were differentially expressed between these tissues. We found that 12% of the miRNAs were significantly differentially expressed between abdominal and gluteal adipose tissue (FDR adjusted p<0.05) in the primary study, of which 59 replicated in a follow-up study of 40 additional subjects. Further, 14 miRNAs were found to be associated with metabolic syndrome case-control status in abdominal tissue and three of these replicated (primary study: FDR adjusted p<0.05, replication: p<0.05 and directionally consistent effect). Genome-wide genotyping was performed in the 70 subjects to enable miRNA expression quantitative trait loci (eQTL) analysis. Candidate miRNA eQTLs were followed-up in the additional 40 subjects and six significant, independent cis-located miRNA eQTLs (primary study: p<0.001; replication: p<0.05 and directionally consistent effect) were identified. Finally, global mRNA expression profiling was performed in both tissues to enable association analysis between miRNA and target mRNA expression levels. We find 22% miRNAs in abdominal and 9% miRNAs in gluteal adipose tissue with expression levels significantly associated with the expression of corresponding target mRNAs (FDR adjusted p<0.05). Taken together, our results indicate a clear difference in the miRNA molecular phenotypic profile of abdominal and gluteal adipose tissue, that the expressions of some miRNAs are influenced by cis-located genetic variants and that miRNAs are associated with expression levels of their predicted mRNA targets.
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Affiliation(s)
- Mattias Rantalainen
- Department of Statistics, University of Oxford, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Blanca M. Herrera
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - George Nicholson
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Rory Bowden
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Quin F. Wills
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Josine L. Min
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Matt J. Neville
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Headington, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, ORH Trust, Churchill Hospital, Oxford, United Kingdom
| | - Amy Barrett
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Headington, Oxford, United Kingdom
| | - Maxine Allen
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Headington, Oxford, United Kingdom
| | - Nigel W. Rayner
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Headington, Oxford, United Kingdom
| | | | - Mark I. McCarthy
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Headington, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, ORH Trust, Churchill Hospital, Oxford, United Kingdom
| | - Krina T. Zondervan
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Headington, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, ORH Trust, Churchill Hospital, Oxford, United Kingdom
| | - Chris C. Holmes
- Department of Statistics, University of Oxford, Oxford, United Kingdom
- MRC Mammalian Genetics Unit, MRC Harwell, Harwell, Oxford, United Kingdom
| | - Cecilia M. Lindgren
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Tussing-Humphreys L, Frayn KN, Smith SR, Westerman M, Dennis AL, Nemeth E, Thomson J, Pusatcioglu C. Subcutaneous adipose tissue from obese and lean adults does not release hepcidin in vivo. ScientificWorldJournal 2011; 11:2197-206. [PMID: 22125467 PMCID: PMC3217603 DOI: 10.1100/2011/634861] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/23/2011] [Indexed: 01/04/2023] Open
Abstract
Hepcidin is the main regulator of systemic iron homeostasis and is primarily produced by the liver but is also expressed, at the mRNA-level, in periphery tissues including the subcutaneous and visceral adipose tissue. Obesity is associated with elevated hepcidin concentrations and iron depletion suggesting that the exaggerated fat mass in obesity could contribute significantly to circulating hepcidin levels consequently altering iron homeostasis. The objective of this study was to determine if abdominal subcutaneous adipose tissue (AbScAT) releases hepcidin in vivo and if release is modified by obesity. Arterio-venous differences in concentrations of hepcidin were measured across AbScAT in 9 obese and 9 lean adults. Overall (n = 18), mean plasma hepcidin concentrations were significantly higher in arterialized compared to AbScAT venous samples [mean difference (arterialized-AbScAT venous plasma hepcidin) = 4.9 ± 9.6 ng/mL, P = 0.04]. Net regional release was not calculated because mean venous plasma hepcidin concentrations were lower than mean arterialized concentrations indicating no net release. Significant correlations between AbScAT venous and arterialized plasma hepcidin concentrations with anthropometric variables were not observed. Findings from this vein drainage study suggest there is no net release of hepcidin from the AbScAT depot and thereby no ability to signal systemically, even in obesity.
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Affiliation(s)
- Lisa Tussing-Humphreys
- USDA Agricultural Research Service, Louisiana State University AgCenter, Knapp Hall, Baton Rouge, LA 70803, USA.
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Affiliation(s)
- Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K.
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Frighi V, Stephenson MT, Morovat A, Jolley IE, Trivella M, Dudley CA, Anand E, White SJ, Hammond CV, Hockney RA, Barrow B, Shakir R, Goodwin GM. Safety of antipsychotics in people with intellectual disability. Br J Psychiatry 2011; 199:289-95. [PMID: 21816867 DOI: 10.1192/bjp.bp.110.085670] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Despite frequent use, little is known about the metabolic and endocrine side-effects of antipsychotics in individuals with intellectual disability. AIMS To compare indices of obesity, glucose, lipids and prolactin between antipsychotic-treated and antipsychotic-naive individuals with intellectual disability and also between participants with intellectual disability and controls from the general population. METHOD Observational study comparing 138 antipsychotic-treated and 64 antipsychotic-naive participants with intellectual disability in one National Health Service trust with general population controls. RESULTS Antipsychotic treatment comprised: risperidone 48%,olanzapine 18%, thioxanthenes 10%, other 24%; monotherapy 95% of participants; mean treatment duration 8 years;median daily chlorpromazine equivalent dose 108 mg(range 16–667). Metabolic indices were the same or more favourable in the intellectual disability group than the general population control group but overweight/obesity and type 2 diabetes were more prevalent in the women in the intellectual disability group than the control group. Metabolic indices were similar, statistically or clinically, between the antipsychotic-treated and the antipsychotic-naive groups but there was a non-significant trend towards a higher rate of type 2 diabetes in the antipsychotic group. A total of 100%and 70% of participants on amisulpride/sulpiride and risperidone respectively had hyperprolactinaemia, with secondary hypogonadism in 77% and 4% of affected women and men. CONCLUSIONS Antipsychotics, on average, did not increase metabolic risk,although the existence of a susceptible subgroup at risk of diabetes cannot be excluded. Some antipsychotics induced hyperprolactinaemic hypogonadism, requiring active management. However, our findings suggest that antipsychotics at the low doses routinely prescribed for people with intellectual disability are generally safe in relation to metabolic adverse effects, even if efficacy remains poorly defined.
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Affiliation(s)
- Valeria Frighi
- Department of Psychiatry, University of Oxford and Ridgeway Partnership (Oxfordshire Learning Disability NHS Trust), Oxford, UK.
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A genome-wide metabolic QTL analysis in Europeans implicates two loci shaped by recent positive selection. PLoS Genet 2011; 7:e1002270. [PMID: 21931564 PMCID: PMC3169529 DOI: 10.1371/journal.pgen.1002270] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 07/15/2011] [Indexed: 12/12/2022] Open
Abstract
We have performed a metabolite quantitative trait locus (mQTL) study of the 1H nuclear magnetic resonance spectroscopy (1H NMR) metabolome in humans, building on recent targeted knowledge of genetic drivers of metabolic regulation. Urine and plasma samples were collected from two cohorts of individuals of European descent, with one cohort comprised of female twins donating samples longitudinally. Sample metabolite concentrations were quantified by 1H NMR and tested for association with genome-wide single-nucleotide polymorphisms (SNPs). Four metabolites' concentrations exhibited significant, replicable association with SNP variation (8.6×10−11<p<2.8×10−23). Three of these—trimethylamine, 3-amino-isobutyrate, and an N-acetylated compound—were measured in urine. The other—dimethylamine—was measured in plasma. Trimethylamine and dimethylamine mapped to a single genetic region (hence we report a total of three implicated genomic regions). Two of the three hit regions lie within haplotype blocks (at 2p13.1 and 10q24.2) that carry the genetic signature of strong, recent, positive selection in European populations. Genes NAT8 and PYROXD2, both with relatively uncharacterized functional roles, are good candidates for mediating the corresponding mQTL associations. The study's longitudinal twin design allowed detailed variance-components analysis of the sources of population variation in metabolite levels. The mQTLs explained 40%–64% of biological population variation in the corresponding metabolites' concentrations. These effect sizes are stronger than those reported in a recent, targeted mQTL study of metabolites in serum using the targeted-metabolomics Biocrates platform. By re-analysing our plasma samples using the Biocrates platform, we replicated the mQTL findings of the previous study and discovered a previously uncharacterized yet substantial familial component of variation in metabolite levels in addition to the heritability contribution from the corresponding mQTL effects. Physiological concentrations of metabolites—small molecules involved in biochemical processes in living systems—can be measured and used to diagnose and predict disease states. A common goal is to detect and clinically exploit statistical differences in metabolite concentrations between diseased and healthy individuals. As a basis for the design and interpretation of case-control studies, it is useful to have a characterization of metabolic diversity amongst healthy individuals, some of which stems from inter-individual genetic variation. When a single genetic locus has a sufficiently strong effect on metabolism, its genomic position can be determined by collecting metabolite concentration data and genome-wide genotype data on a set of individuals and searching for associations between the two data sets—a so-called metabolite quantitative trait locus (mQTL) study. By so tracing mQTLs, we can identify the genetic drivers of metabolism, characterize how the nature or quantity of the corresponding expressed protein(s) feeds forward to influence metabolite levels, and specify disease-predictive models that incorporate mutual dependence amongst genetics, environment, and metabolism.
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Neville MJ, Collins JM, Gloyn AL, McCarthy MI, Karpe F. Comprehensive human adipose tissue mRNA and microRNA endogenous control selection for quantitative real-time-PCR normalization. Obesity (Silver Spring) 2011; 19:888-92. [PMID: 20948521 PMCID: PMC4623139 DOI: 10.1038/oby.2010.257] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The accurate quantification of cellular and tissue mRNA and microRNA content is reliant upon the selection of stable endogenous control transcripts for normalizing quantitative real-time-PCR (qRT-PCR) data. Using the combination of unbiased and informed approaches and a wide range of human adipose tissues and cells, we sought to identify invariant control transcripts for mRNA and microRNA. A total of 26 mRNA transcript candidates were selected from the literature. MicroRNA candidates were selected from a microRNA-microarray (Agilent, n = 22 tissues), and together with candidates from the literature resulted in 14 different microRNAs. The variability of these mRNA and microRNA transcripts were then tested in a large (n = 180) collection of a variety of human adipose tissues and cell samples. Phosphoglycerate kinase-1 (PGK1) and peptidylprolyl isomerase A (PPIA) were identified as the most stable mRNAs across all tissues and panels. MiR-103 was overall the most stable microRNA transcript across all biological backgrounds. Several proposed and commonly used normalization transcripts were found to be highly variable. We then tested the effect on expression of two established adipocyte-related transcripts (fatty acid binding protein 4 (FABP4) and microRNA-145 (miR-145)), either normalized to the optimal or a commonly used controls transcript. This test clearly indicated that spurious results could arise from using less stable control transcripts for mRNA and microRNA qRT-PCR.
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Affiliation(s)
- Matt J Neville
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK.
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Young women partition fatty acids towards ketone body production rather than VLDL-TAG synthesis, compared with young men. Br J Nutr 2011; 105:857-65. [PMID: 21251339 DOI: 10.1017/s0007114510004472] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Before the menopause, women are relatively protected against CVD compared with men. The reasons for this sex difference are not completely understood, but hepatic fatty acid metabolism may play a role. The present study aimed to investigate the utilisation of plasma NEFA by the liver and to determine whether they are partitioned differently into ketone bodies and VLDL-TAG in healthy, lean young men and women. Volunteers were studied during a prolonged overnight fast (12-19 h) using an intravenous infusion of [U-¹³C]palmitate. After 12 h fasting, the women had a more advantageous metabolic profile with lower plasma glucose (P < 0·05) and TAG (P < 0·05) but higher plasma NEFA (P < 0·05) concentrations. Plasma 3-hydroxybutyrate (3-OHB) concentrations rose more in women than in men, and the transfer of ¹³C from [U-¹³C]palmitate to plasma [¹³C]3-OHB reached a plateau 6-7 h after the start of the infusion in women but was still increasing at 6 h in men. This implies a slower 3-OHB production rate and/or dilution by other precursor pools in men. In women, the high isotopic enrichment of plasma 3-OHB suggested that systemic plasma fatty acids were the major source of 3-OHB production. However, in men, this was not observed during the course of the study (P < 0·01). There were no sex differences for the incorporation of ¹³C into VLDL1- or VLDL2-TAG. The ability of young women to partition fatty acids towards ketone body production rather than VLDL-TAG may contribute to their more advantageous metabolic profile compared with young men.
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McQuaid SE, Hodson L, Neville MJ, Dennis AL, Cheeseman J, Humphreys SM, Ruge T, Gilbert M, Fielding BA, Frayn KN, Karpe F. Downregulation of adipose tissue fatty acid trafficking in obesity: a driver for ectopic fat deposition? Diabetes 2011; 60:47-55. [PMID: 20943748 PMCID: PMC3012196 DOI: 10.2337/db10-0867] [Citation(s) in RCA: 248] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Lipotoxicity and ectopic fat deposition reduce insulin signaling. It is not clear whether excess fat deposition in nonadipose tissue arises from excessive fatty acid delivery from adipose tissue or from impaired adipose tissue storage of ingested fat. RESEARCH DESIGN AND METHODS To investigate this we used a whole-body integrative physiological approach with multiple and simultaneous stable-isotope fatty acid tracers to assess delivery and transport of endogenous and exogenous fatty acid in adipose tissue over a diurnal cycle in lean (n = 9) and abdominally obese men (n = 10). RESULTS Abdominally obese men had substantially (2.5-fold) greater adipose tissue mass than lean control subjects, but the rates of delivery of nonesterified fatty acids (NEFA) were downregulated, resulting in normal systemic NEFA concentrations over a 24-h period. However, adipose tissue fat storage after meals was substantially depressed in the obese men. This was especially so for chylomicron-derived fatty acids, representing the direct storage pathway for dietary fat. Adipose tissue from the obese men showed a transcriptional signature consistent with this impaired fat storage function. CONCLUSIONS Enlargement of adipose tissue mass leads to an appropriate downregulation of systemic NEFA delivery with maintained plasma NEFA concentrations. However the implicit reduction in adipose tissue fatty acid uptake goes beyond this and shows a maladaptive response with a severely impaired pathway for direct dietary fat storage. This adipose tissue response to obesity may provide the pathophysiological basis for ectopic fat deposition and lipotoxicity.
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Affiliation(s)
- Siobhán E. McQuaid
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - Matthew J. Neville
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - A. Louise Dennis
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - Jane Cheeseman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
- National Institute for Health Research, Oxford Biomedical Research Centre, Oxford Radcliffe Hospitals Trust, Oxford, U.K
| | - Sandy M. Humphreys
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - Toralph Ruge
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - Marjorie Gilbert
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - Barbara A. Fielding
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - Keith N. Frayn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, U.K
- National Institute for Health Research, Oxford Biomedical Research Centre, Oxford Radcliffe Hospitals Trust, Oxford, U.K
- Corresponding author: Fredrik Karpe,
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Hodson L, McQuaid SE, Humphreys SM, Milne R, Fielding BA, Frayn KN, Karpe F. Greater dietary fat oxidation in obese compared with lean men: an adaptive mechanism to prevent liver fat accumulation? Am J Physiol Endocrinol Metab 2010; 299:E584-92. [PMID: 20628024 PMCID: PMC2957864 DOI: 10.1152/ajpendo.00272.2010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Liver fat represents a balance between input, secretion, and oxidation of fatty acids. As humans spend the majority of a 24-h period in a postprandial state, dietary fatty acids make an important contribution to liver fat metabolism. We compared hepatic fatty acid partitioning in healthy lean (n = 9) and abdominally obese (n = 10) males over 24 h. Volunteers received three mixed meals adjusted for basal metabolic rate. U-13C-labeled fatty acids were incorporated into the meals, and [2H2]palmitate was infused intravenously to distinguish between sources of fatty acids incorporated into VLDL-TG. Immunoaffinity chromatography was used to isolate VLDL-TG of hepatic origin. Liver and whole body fatty acid oxidation was assessed by isotopic enrichment of 3-hydoxybutyrate and breath CO2. We found a similar contribution of dietary fatty acids to VLDL-TG in the two groups over 24 h. The contribution of fatty acids from splanchnic sources was higher (P < 0.05) in the abdominally obese group. Ketogenesis occurred to a significantly greater extent in abdominally obese compared with lean males, largely due to lessened downregulation of postprandial ketogenesis (P < 0.001). The appearance of 13C in breath CO2 was also greater (P < 0.001) in abdominally obese compared with lean men. Hepatic elongation and desaturation of palmitic acid were higher (P < 0.05) in abdominally obese than in lean males. Oxidation of dietary fatty acids and hepatic desaturation and elongation of palmitic acid occurred to a greater extent in abdominally obese men. These alterations may represent further pathways for redirection of fatty acids into export from the liver or oxidation to prevent liver fat accumulation.
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Affiliation(s)
- Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom.
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McQuaid SE, Humphreys SM, Hodson L, Fielding BA, Karpe F, Frayn KN. Femoral adipose tissue may accumulate the fat that has been recycled as VLDL and nonesterified fatty acids. Diabetes 2010; 59:2465-73. [PMID: 20682685 PMCID: PMC3279526 DOI: 10.2337/db10-0678] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Gluteo-femoral, in contrast to abdominal, fat accumulation appears protective against diabetes and cardiovascular disease. Our objective was to test the hypothesis that this reflects differences in the ability of the two depots to sequester fatty acids, with gluteo-femoral fat acting as a longer-term "sink." RESEARCH DESIGN AND METHODS A total of 12 healthy volunteers were studied after an overnight fast and after ingestion of a mixed meal. Blood samples were taken from veins draining subcutaneous femoral and abdominal fat and compared with arterialized blood samples. Stable isotope-labeled fatty acids were used to trace specific lipid fractions. In 36 subjects, adipose tissue blood flow in the two depots was monitored with (133)Xe. RESULTS Blood flow increased in response to the meal in both depots, and these responses were correlated (r(s) = 0.44, P < 0.01). Nonesterified fatty acid (NEFA) release was suppressed after the meal in both depots; it was lower in femoral fat than in abdominal fat (P < 0.01). Plasma triacylglycerol (TG) extraction by femoral fat was also lower than that by abdominal fat (P = 0.05). Isotopic tracers showed that the difference was in chylomicron-TG extraction. VLDL-TG extraction and direct NEFA uptake were similar in the two depots. CONCLUSIONS Femoral fat shows lower metabolic fluxes than subcutaneous abdominal fat, but differs in its relative preference for extracting fatty acids directly from the plasma NEFA and VLDL-TG pools compared with chylomicron-TG.
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Affiliation(s)
- Siobhán E. McQuaid
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Oxford, U.K
| | - Sandy M. Humphreys
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Oxford, U.K
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Oxford, U.K
| | - Barbara A. Fielding
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Oxford, U.K
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Oxford, U.K
- National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, Oxford Radcliffe Hospitals, Oxford, U.K
| | - Keith N. Frayn
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Oxford, U.K
- Corresponding author: Keith N. Frayn,
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Regulation of subcutaneous adipose tissue blood flow is related to measures of vascular and autonomic function. Clin Sci (Lond) 2010; 119:313-22. [PMID: 20518748 DOI: 10.1042/cs20100066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Appropriate blood vessel function is important to cardiovascular health. Adipose tissue plays an important role in metabolic homoeostasis, and subcutaneous abdominal ATBF (adipose tissue blood flow) is responsive to nutritional stimuli. This response is impaired in obesity, suggesting parallels with endothelial function. In the present study, we assessed whether regulation of ATBF is related to the regulation of endothelial function, assessed by FMD (flow-mediated vasodilatation) of the brachial artery. Impaired FMD is a marker of atherosclerotic risk, so we also assessed relationships between ATBF and a marker of atherosclerosis, common carotid artery IMT (intima-media thickness). As ATBF is responsive to sympatho-adrenal stimuli, we also investigated relationships with HRV (heart rate variability). A total of 79 healthy volunteers (44 female) were studied after fasting and after ingestion of 75 g of glucose. FMD, fasting ATBF and the responsiveness of ATBF to glucose were all negatively related to BMI (body mass index), confirming the adverse cardiovascular effects of adiposity. FMD was related to fasting ATBF (rs=0.32, P=0.008) and, at least in males, this relationship was independent of BMI (P=0.02). Common carotid artery IMT, measured in a subset of participants, was negatively related to fasting ATBF [rs=-0.51, P=0.02 (n=20)]. On the other hand, ATBF responsiveness to glucose had no relationship with either FMD or IMT. In multiple regression models, both fasting and stimulated ATBF had relationships with HRV. In conclusion, our results show that the regulation of ATBF has features in common with endothelial function, but also relationships with autonomic cardiovascular control as reflected in HRV.
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Mejhert N, Galitzky J, Pettersson AT, Bambace C, Blomqvist L, Bouloumié A, Frayn KN, Dahlman I, Arner P, Rydén M. Mapping of the fibroblast growth factors in human white adipose tissue. J Clin Endocrinol Metab 2010; 95:2451-7. [PMID: 20228166 DOI: 10.1210/jc.2009-2049] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
CONTEXT Fibroblast growth factors (FGFs) regulate the development of white adipose tissue (WAT). However, the secretion and cellular origin of individual FGFs in WAT as well as the influence of obesity are unknown. OBJECTIVE Our objective was to map FGFs in human sc WAT, the cellular source, and association with obesity. DESIGN Secretion, mRNA, and circulatory levels of FGFs in human abdominal sc WAT from nonobese and obese donors were examined by microarray, real-time quantitative PCR, and ELISA. The activity of FGFs in cultured human adipocytes was determined by phosphorylation assays. RESULTS Expression of five FGFs (FGF1, FGF2, FGF7, FGF9, and FGF18) and FGF homologous factor (FHF2) was identified in WAT. Only FGF1 was released in a time-dependent manner from sc WAT, and fat cells were the major source of FGF1 secretion. FGF1 expression increased and FGF2 decreased during adipocyte differentiation. Furthermore, FGF1 was not secreted into the circulation. Although FGF1 levels were 2-fold increased in obesity, they were unaltered by weight reduction. Only FGF1 and FGF2 induced a marked concentration-dependent phosphorylation of p44/42 in cultured human adipocytes. CONCLUSIONS Of the investigated FGFs, only FGF1 is secreted from sc WAT and predominantly so from the adipocyte fraction. The activity in adipocyte cultures and lack of secretion into the circulation suggest that FGF1 acts as an auto- or paracrine factor. FGF1 levels are increased in obesity but unaffected by weight reduction, suggesting a primary defect in obese individuals. In conclusion, FGF1 may play a superior role among the FGFs in sc WAT and obesity development.
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Affiliation(s)
- Niklas Mejhert
- Karolinska Institutet, Department of Medicine, Huddinge, Lipid Laboratory, Stockholm, Sweden.
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