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Yang Z, Chen F, Zhang Y, Ou M, Tan P, Xu X, Li Q, Zhou S. Therapeutic targeting of white adipose tissue metabolic dysfunction in obesity: mechanisms and opportunities. MedComm (Beijing) 2024; 5:e560. [PMID: 38812572 PMCID: PMC11134193 DOI: 10.1002/mco2.560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 04/09/2024] [Accepted: 04/14/2024] [Indexed: 05/31/2024] Open
Abstract
White adipose tissue is not only a highly heterogeneous organ containing various cells, such as adipocytes, adipose stem and progenitor cells, and immune cells, but also an endocrine organ that is highly important for regulating metabolic and immune homeostasis. In individuals with obesity, dynamic cellular changes in adipose tissue result in phenotypic switching and adipose tissue dysfunction, including pathological expansion, WAT fibrosis, immune cell infiltration, endoplasmic reticulum stress, and ectopic lipid accumulation, ultimately leading to chronic low-grade inflammation and insulin resistance. Recently, many distinct subpopulations of adipose tissue have been identified, providing new insights into the potential mechanisms of adipose dysfunction in individuals with obesity. Therefore, targeting white adipose tissue as a therapeutic agent for treating obesity and obesity-related metabolic diseases is of great scientific interest. Here, we provide an overview of white adipose tissue remodeling in individuals with obesity including cellular changes and discuss the underlying regulatory mechanisms of white adipose tissue metabolic dysfunction. Currently, various studies have uncovered promising targets and strategies for obesity treatment. We also outline the potential therapeutic signaling pathways of targeting adipose tissue and summarize existing therapeutic strategies for antiobesity treatment including pharmacological approaches, lifestyle interventions, and novel therapies.
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Affiliation(s)
- Zi‐Han Yang
- Department of Plastic and Burn SurgeryWest China Hospital of Sichuan UniversityChengduChina
- Department of Plastic & Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Fang‐Zhou Chen
- Department of Plastic & Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yi‐Xiang Zhang
- Department of Plastic & Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Min‐Yi Ou
- Department of Plastic & Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Poh‐Ching Tan
- Department of Plastic & Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Xue‐Wen Xu
- Department of Plastic and Burn SurgeryWest China Hospital of Sichuan UniversityChengduChina
| | - Qing‐Feng Li
- Department of Plastic & Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Shuang‐Bai Zhou
- Department of Plastic & Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
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Tanriover C, Copur S, Gaipov A, Ozlusen B, Akcan RE, Kuwabara M, Hornum M, Van Raalte DH, Kanbay M. Metabolically healthy obesity: Misleading phrase or healthy phenotype? Eur J Intern Med 2023; 111:5-20. [PMID: 36890010 DOI: 10.1016/j.ejim.2023.02.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/16/2023] [Accepted: 02/27/2023] [Indexed: 03/08/2023]
Abstract
Obesity is a heterogenous condition with multiple different phenotypes. Among these a particular subtype exists named as metabolically healthy obesity (MHO). MHO has multiple definitions and its prevalence varies according to study. The potential mechanisms underlying the pathophysiology of MHO include the different types of adipose tissue and their distribution, the role of hormones, inflammation, diet, the intestinal microbiota and genetic factors. In contrast to the negative metabolic profile associated with metabolically unhealthy obesity (MUO), MHO has relatively favorable metabolic characteristics. Nevertheless, MHO is still associated with many important chronic diseases including cardiovascular disease, hypertension, type 2 diabetes, chronic kidney disease as well as certain types of cancer and has the risk of progression into the unhealthy phenotype. Therefore, it should not be considered as a benign condition. The major therapeutic alternatives include dietary modifications, exercise, bariatric surgery and certain medications including glucagon-like peptide-1 (GLP-1) analogs, sodium-glucose cotransporter-2 (SGLT-2) inhibitors and tirzepatide. In this review, we discuss the significance of MHO while comparing this phenotype with MUO.
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Affiliation(s)
- Cem Tanriover
- Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| | - Sidar Copur
- Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| | - Abduzhappar Gaipov
- Department of Medicine, Nazarbayev University School of Medicine, Astana, Kazakhstan; Clinical Academic Department of Internal Medicine, CF "University Medical Center", Astana, Kazakhstan
| | - Batu Ozlusen
- Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| | - Rustu E Akcan
- Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| | | | - Mads Hornum
- Department of Nephrology, Rigshospitalet, Inge Lehmanns Vej 7, Copenhagen 2100, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Daniel H Van Raalte
- Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Center, Loaction VUMC, Amsterdam, the Netherlands
| | - Mehmet Kanbay
- Department of Medicine, Division of Nephrology, Koc University School of Medicine, Istanbul 34010, Turkey.
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Pathogenesis, Murine Models, and Clinical Implications of Metabolically Healthy Obesity. Int J Mol Sci 2022; 23:ijms23179614. [PMID: 36077011 PMCID: PMC9455655 DOI: 10.3390/ijms23179614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/21/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
Although obesity is commonly associated with numerous cardiometabolic pathologies, some people with obesity are resistant to detrimental effects of excess body fat, which constitutes a condition called “metabolically healthy obesity” (MHO). Metabolic features of MHO that distinguish it from metabolically unhealthy obesity (MUO) include differences in the fat distribution, adipokine types, and levels of chronic inflammation. Murine models are available that mimic the phenotype of human MHO, with increased adiposity but preserved insulin sensitivity. Clinically, there is no established definition of MHO yet. Despite the lack of a uniform definition, most studies describe MHO as a particular case of obesity with no or only one metabolic syndrome components and lower levels of insulin resistance or inflammatory markers. Another clinical viewpoint is the dynamic and changing nature of MHO, which substantially impacts the clinical outcome. In this review, we explore the pathophysiology and some murine models of MHO. The definition, variability, and clinical implications of the MHO phenotype are also discussed. Understanding the characteristics that differentiate people with MHO from those with MUO can lead to new insights into the mechanisms behind obesity-related metabolic derangements and diseases.
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Abstract
Obesity is a chronic and progressive process affecting whole-body energy balance and is associated with comorbidities development. In addition to increased fat mass, obesity induces white adipose tissue (WAT) inflammation and fibrosis, leading to local and systemic metabolic dysfunctions, such as insulin resistance (IR). Accordingly, limiting inflammation or fibrosis deposition may improve IR and glucose homeostasis. Although no targeted therapy yet exists to slow or reverse adipose tissue fibrosis, a number of findings have clarified the underlying cellular and molecular mechanisms. In this review, we highlight adipose tissue remodeling events shown to be associated with fibrosis deposition, with a focus on adipose progenitors involved in obesity-induced healthy as well as unhealthy WAT expansion. Expected final online publication date for the Annual Review of Physiology, Volume 84 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Geneviève Marcelin
- INSERM, Nutrition and Obesities: Systemic Approach (NutriOmics) Research Unit, UMRS U1269, Sorbonne Université, Paris, France; ,
| | | | - Karine Clément
- INSERM, Nutrition and Obesities: Systemic Approach (NutriOmics) Research Unit, UMRS U1269, Sorbonne Université, Paris, France; , .,Nutrition Department, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
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Rodríguez C, Sánchez A, Sáenz-Medina J, Muñoz M, Hernández M, López M, Rivera L, Contreras C, Prieto D. Activation of AMP kinase ameliorates kidney vascular dysfunction, oxidative stress and inflammation in rodent models of obesity. Br J Pharmacol 2021; 178:4085-4103. [PMID: 34192805 DOI: 10.1111/bph.15600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND AND PURPOSE Obesity is a risk factor for the development of chronic kidney disease independent of diabetes, hypertension and other co-morbidities. Obesity-associated nephropathy is linked to dysregulation of the cell energy sensor AMP-activated protein kinase (AMPK). We aimed here to assess whether impairment of AMPK activity may cause renal arterial dysfunction in obesity and to evaluate the therapeutic potential of activating renal AMPK. EXPERIMENTAL APPROACH Effects of the AMPK activator A769662 were assessed on intrarenal arteries isolated from ob/ob mice and obese Zucker rats and then mounted in microvascular myographs. Superoxide and hydrogen peroxide production were measured by chemiluminescence and fluorescence, respectively, and protein expression was analysed by western blotting. KEY RESULTS Endothelium-dependent vasodilation and PI3K/Akt/eNOS pathway were impaired in preglomerular arteries from genetically obese rats and mice, along with impaired arterial AMPK activity and blunted relaxations induced by the AMPK activator A769662. Acute ex vivo exposure to A769662 restored endothelial function and enhanced activity of PI3K/Akt/eNOS pathway in obese rats, whereas in vivo treatment with A769662 improved metabolic state and ameliorated endothelial dysfunction, reduced inflammatory markers and vascular oxidative stress in renal arteries and restored redox balance in renal cortex of obese mice. CONCLUSION AND IMPLICATIONS These results demonstrate that AMPK dysregulation underlies obesity-associated kidney vascular dysfunction and activation of AMPK improves metabolic state, protects renal endothelial function and exerts potent vascular antioxidant and anti-inflammatory effects. The beneficial effects of vascular AMPK activation might represent a promising therapeutic approach to the treatment of obesity-related kidney injury.
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Affiliation(s)
- Claudia Rodríguez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Ana Sánchez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Javier Sáenz-Medina
- Departamento de Urología, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid, Spain
| | - Mercedes Muñoz
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Medardo Hernández
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Miguel López
- NeurObesity Group, Department of Physiology, CIMUS, Universidad de Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
| | - Luis Rivera
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Cristina Contreras
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Dolores Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
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Ahmed B, Sultana R, Greene MW. Adipose tissue and insulin resistance in obese. Biomed Pharmacother 2021; 137:111315. [PMID: 33561645 DOI: 10.1016/j.biopha.2021.111315] [Citation(s) in RCA: 280] [Impact Index Per Article: 93.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 02/08/2023] Open
Abstract
Currently, obesity has become a global health issue and is referred to as an epidemic. Dysfunctional obese adipose tissue plays a pivotal role in the development of insulin resistance. However, the mechanism of how dysfunctional obese-adipose tissue develops insulin-resistant circumstances remains poorly understood. Therefore, this review attempts to highlight the potential mechanisms behind obesity-associated insulin resistance. Multiple risk factors are directly or indirectly associated with the increased risk of obesity; among them, environmental factors, genetics, aging, gut microbiota, and diets are prominent. Once an individual becomes obese, adipocytes increase in their size; therefore, adipose tissues become larger and dysfunctional, recruit macrophages, and then these polarize to pro-inflammatory states. Enlarged adipose tissues release excess free fatty acids (FFAs), reactive oxygen species (ROS), and pro-inflammatory cytokines. Excess systemic FFAs and dietary lipids enter inside the cells of non-adipose organs such as the liver, muscle, and pancreas, and are deposited as ectopic fat, generating lipotoxicity. Toxic lipids dysregulate cellular organelles, e.g., mitochondria, endoplasmic reticulum, and lysosomes. Dysregulated organelles release excess ROS and pro-inflammation, resulting in systemic inflammation. Long term low-grade systemic inflammation prevents insulin from its action in the insulin signaling pathway, disrupts glucose homeostasis, and results in systemic dysregulation. Overall, long-term obesity and overnutrition develop into insulin resistance and chronic low-grade systemic inflammation through lipotoxicity, creating the circumstances to develop clinical conditions. This review also shows that the liver is the most sensitive organ undergoing insulin impairment faster than other organs, and thus, hepatic insulin resistance is the primary event that leads to the subsequent development of peripheral tissue insulin resistance.
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Affiliation(s)
- Bulbul Ahmed
- Department of Nutrition, Auburn University, Auburn, AL, 36849, United States.
| | - Rifat Sultana
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, United States
| | - Michael W Greene
- Department of Nutrition, Auburn University, Auburn, AL, 36849, United States
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Rasouli N, Younes N, Utzschneider KM, Inzucchi SE, Balasubramanyam A, Cherrington AL, Ismail-Beigi F, Cohen RM, Olson DE, DeFronzo RA, Herman WH, Lachin JM, Kahn SE. Association of Baseline Characteristics With Insulin Sensitivity and β-Cell Function in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE) Study Cohort. Diabetes Care 2021; 44:340-349. [PMID: 33334808 PMCID: PMC7818323 DOI: 10.2337/dc20-1787] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/11/2020] [Indexed: 02/03/2023]
Abstract
OBJECTIVE We investigated sex and racial differences in insulin sensitivity, β-cell function, and glycated hemoglobin (HbA1c) and the associations with selected phenotypic characteristics. RESEARCH DESIGN AND METHODS This is a cross-sectional analysis of baseline data from 3,108 GRADE (Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study) participants. All had type 2 diabetes diagnosed <10 years earlier and were on metformin monotherapy. Insulin sensitivity and β-cell function were evaluated using the HOMA of insulin sensitivity and estimates from oral glucose tolerance tests, including the Matsuda Index, insulinogenic index, C-peptide index, and oral disposition index (DI). RESULTS The cohort was 56.6 ± 10 years of age (mean ± SD), 63.8% male, with BMI 34.2 ± 6.7 kg/m2, HbA1c 7.5 ± 0.5%, and type 2 diabetes duration 4.0 ± 2.8 years. Women had higher DI than men but similar insulin sensitivity. DI was the highest in Black/African Americans, followed by American Indians/Alaska Natives, Asians, and Whites in descending order. Compared with Whites, American Indians/Alaska Natives had significantly higher HbA1c, but Black/African Americans and Asians had lower HbA1c. However, when adjusted for glucose levels, Black/African Americans had higher HbA1c than Whites. Insulin sensitivity correlated inversely with BMI, waist-to-hip ratio, triglyceride-to-HDL-cholesterol ratio (TG/HDL-C), and the presence of metabolic syndrome, whereas DI was associated directly with age and inversely with BMI, HbA1c, and TG/HDL-C. CONCLUSIONS In the GRADE cohort, β-cell function differed by sex and race and was associated with the concurrent level of HbA1c. HbA1c also differed among the races, but not by sex. Age, BMI, and TG/HDL-C were associated with multiple measures of β-cell function and insulin sensitivity.
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Affiliation(s)
- Neda Rasouli
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado School of Medicine, Aurora, CO
- VA Eastern Colorado Health Care System, Aurora, CO
| | - Naji Younes
- The Biostatistics Center, Department of Biostatistics and Bioinformatics, Milken Institute School of Public Health, The George Washington University, Rockville, MD
| | - Kristina M Utzschneider
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and the University of Washington, Seattle, WA
| | | | - Ashok Balasubramanyam
- Division of Diabetes, Endocrinology and Metabolism, Baylor College of Medicine, Houston, TX
| | | | - Faramarz Ismail-Beigi
- Department of Medicine, Case Western Reserve University and Louis Stokes Cleveland VA Medical Center, Cleveland, OH
| | - Robert M Cohen
- Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati College of Medicine and Cincinnati VA Medical Center, Cincinnati, OH
| | - Darin E Olson
- Atlanta VA Health Care System and Division of Endocrinology, Metabolism, and Lipids, Department of Medicine, Emory University School of Medicine, Atlanta, GA
| | - Ralph A DeFronzo
- University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - William H Herman
- Departments of Internal Medicine and Epidemiology, University of Michigan, Ann Arbor, MI
| | - John M Lachin
- The Biostatistics Center, Department of Biostatistics and Bioinformatics, Milken Institute School of Public Health, The George Washington University, Rockville, MD
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and the University of Washington, Seattle, WA
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Liu J, Yang R, Meng H, Zhou T, He Q. In vitro treatment of 3 T3-L1 adipocytes with recombinant Calcium/calmodulin-dependent Protein Kinase IV (CaMKIV) limits ER stress and improves insulin sensitivity through inhibition of autophagy via the mTOR/CREB signaling pathway. BMC Endocr Disord 2020; 20:104. [PMID: 32660483 PMCID: PMC7359471 DOI: 10.1186/s12902-020-00589-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 07/07/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Recently, CaMKIV has been identified as a potential regulator of skeletal muscle glucose metabolism, it can also affect insulin gene expression in pancreas. However, its effects on adipose insulin resistance have yet to be explored. Autophagy has been shown as a potential therapeutic target for ER (endoplasmic reticulum) stress and insulin resistance. The purpose of this study is to investigate the effects of CaMKIV on ER stress, autophagic function and insulin signaling in tunicamycin-treated adipocytes. METHODS In this study, mature 3 T3-L1 adipocytes were treated with tunicamycin to induce ER stress. Tunicamycin-treated 3 T3-L1 adipocytes were treated with recombinant CaMKIV in the presence or absence of targeted-siRNA mediated down-regulation of CREB and mTOR. The ER stress markers, autophagy activation, mTOR/CREB signaling and insulin sensitivity were analyzed by western blotting or electron microscopy. RESULTS Treatment with CaMKIV significantly reversed tunicamycin-induced expression of p-PERK, cleaved-ATF6, Atg7 and LC3II. It also reduced p62 expression. In addition, levels of p-Akt and p-IRS-1 were increased. Moreover, CaMKIV inhibited activated ER stress and insulin resistance in Atg7 siRNA transfected adipocytes. However, the protective effects of CaMKIV on ER stress, insulin signaling, and autophagy function were nullified by suppression of mTOR or CREB in tunicamycin-treated adipocytes. CONCLUSION This study proves recombinant CaMKIV inhibits tunicamycin-induced ER stress and insulin resistance by regulating autophagy. The protective effect of CaMKIV in adipocytes is affected at least partly through mTOR/CREB signaling. Our finding may offer novel opportunities for treating obesity and type 2 diabetes.
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Affiliation(s)
- Jiali Liu
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Ruihua Yang
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China
| | - Hao Meng
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China
| | - Ting Zhou
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China
| | - Qian He
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China.
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Smith GI, Mittendorfer B, Klein S. Metabolically healthy obesity: facts and fantasies. J Clin Invest 2020; 129:3978-3989. [PMID: 31524630 DOI: 10.1172/jci129186] [Citation(s) in RCA: 338] [Impact Index Per Article: 84.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Although obesity is typically associated with metabolic dysfunction and cardiometabolic diseases, some people with obesity are protected from many of the adverse metabolic effects of excess body fat and are considered "metabolically healthy." However, there is no universally accepted definition of metabolically healthy obesity (MHO). Most studies define MHO as having either 0, 1, or 2 metabolic syndrome components, whereas many others define MHO using the homeostasis model assessment of insulin resistance (HOMA-IR). Therefore, numerous people reported as having MHO are not metabolically healthy, but simply have fewer metabolic abnormalities than those with metabolically unhealthy obesity (MUO). Nonetheless, a small subset of people with obesity have a normal HOMA-IR and no metabolic syndrome components. The mechanism(s) responsible for the divergent effects of obesity on metabolic health is not clear, but studies conducted in rodent models suggest that differences in adipose tissue biology in response to weight gain can cause or prevent systemic metabolic dysfunction. In this article, we review the definition, stability over time, and clinical outcomes of MHO, and discuss the potential factors that could explain differences in metabolic health in people with MHO and MUO - specifically, modifiable lifestyle factors and adipose tissue biology. Better understanding of the factors that distinguish people with MHO and MUO can produce new insights into mechanism(s) responsible for obesity-related metabolic dysfunction and disease.
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Pierzynová A, Šrámek J, Cinkajzlová A, Kratochvílová H, Lindner J, Haluzík M, Kučera T. The number and phenotype of myocardial and adipose tissue CD68+ cells is associated with cardiovascular and metabolic disease in heart surgery patients. Nutr Metab Cardiovasc Dis 2019; 29:946-955. [PMID: 31307852 DOI: 10.1016/j.numecd.2019.05.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/26/2019] [Accepted: 05/17/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS CD68+ cells are a potent source of inflammatory cytokines in adipose tissue and myocardium. The development of low-grade inflammation in adipose tissue is implicated in the pathogenesis of obesity-associated disorders including type 2 diabetes mellitus (T2DM) and cardiovascular disease. The main aim of the study was to characterize and quantify myocardial and adipose tissue CD68+ cells and adipose tissue crown-like structures (CLS) in patients with obesity, coronary artery disease (CAD) and T2DM. METHODS AND RESULTS Samples were obtained from the right atrium, epicardial (EAT) and subcutaneous adipose tissue (SAT) during elective heart surgery (non-obese, n = 34 patients; obese, n = 24 patients). Immunohistochemistry was used to visualize CD68+ cells. M1-polarized macrophages were visualized by immunohistochemical detection of CD11c. The proportion of CD68+ cells was higher in EAT than in SAT (43.4 ± 25.0 versus 32.5 ± 23.1 cells per 1 mm2; p = 0.015). Myocardial CD68+ cells were more abundant in obese patients (45.6 ± 24.5 versus 27.7 ± 14.8 cells per 1 mm2; p = 0.045). In SAT, CD68+ cells were more frequent in CAD patients (37.3 ± 23.0 versus 23.1 ± 20.9 cells per 1 mm2; p = 0.012). Patients having CLS in their SAT had higher average BMI (34.1 ± 6.4 versus 29.0 ± 4.5; p = 0.024). CONCLUSIONS Regional-based increases in the frequency of CD68+ cells and changes of their phenotype in CLS were detected in obese patients and CAD patients. Therapeutic modulation of adipose tissue inflammation may represent a target for treatment of obesity.
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Affiliation(s)
- Aneta Pierzynová
- Institute of Histology and Embryology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jaromír Šrámek
- Institute of Histology and Embryology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Anna Cinkajzlová
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; Department of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Helena Kratochvílová
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; Department of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Jaroslav Lindner
- 2nd Department of Surgery - Department of Cardiovascular Surgery, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Martin Haluzík
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; Department of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Tomáš Kučera
- Institute of Histology and Embryology, First Faculty of Medicine, Charles University, Prague, Czech Republic.
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Allister-Price C, Craig CM, Spielman D, Cushman SS, McLaughlin TL. Metabolic markers, regional adiposity, and adipose cell size: relationship to insulin resistance in African-American as compared with Caucasian women. Int J Obes (Lond) 2019; 43:1164-1173. [PMID: 30127463 PMCID: PMC6382609 DOI: 10.1038/s41366-018-0191-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/22/2018] [Accepted: 07/22/2018] [Indexed: 01/22/2023]
Abstract
BACKGROUND/OBJECTIVES African-American women have the greatest prevalence of obesity in the United States, and higher rates of type 2 diabetes than Caucasian women, yet paradoxically lower plasma triglycerides (TG), visceral fat and intrahepatic fat, and higher high-density lipoprotein (HDL)-cholesterol. Visceral fat has not been evaluated against insulin resistance in African-American women, and TG/HDL-cholesterol has been criticized as a poor biomarker for insulin resistance in mixed-sex African-American populations. Adipocyte hypertrophy, reflecting adipocyte dysfunction, predicts insulin resistance in Caucasians, but has not been studied in African-Americans. Our goal was to assess whether traditional correlates of insulin resistance, measures of adiposity and adipocyte characteristics similarly predict peripheral insulin resistance in African-American and Caucasian women. SUBJECTS/METHODS Thirty-four healthy African-American (n = 17) and Caucasian (n = 17) women, matched for age (mean = 53.0 yrs) and body mass index (BMI) (mean = 30 kg/m2), underwent a steady-state plasma glucose test to measure insulin sensitivity; computed tomography (fat distribution); and a periumbilical scalpel biopsy (adipocyte characterization). By-race analyzes utilized analysis of covariance; linear regressions evaluated relationships between metabolic/adipose variables. All analyses adjusted for BMI and menopausal status. RESULTS Insulin sensitivity did not differ between groups (p = 0.65). Neither BMI, nor %body fat or thigh fat predicted insulin resistance in African-American women. Fasting TG (p = 0.046), HDL-cholesterol (p = 0.0006) and TG/HDL-cholesterol ratio (p = 0.009) strongly predicted insulin resistance in African-American women. Despite being lower in African-American women, hepatic fat and visceral adipose tissue (VAT) correlated with insulin resistance in both groups, as did fasting glucose, VAT/SAT (subcutaneous adipose tissue) ratio, and %SAT (inverse). CONCLUSIONS Total adiposity measures and adipocyte hypertrophy did not predict insulin resistance in African-American women, but did in Caucasian women. Plasma TG and HDL-cholesterol were significant predictors of insulin resistance in African-American women. Our findings demonstrate the need to identify race and sex-specific biomarkers for metabolic risk profiling.
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Affiliation(s)
- Candice Allister-Price
- Department of Molecular Biology, School of Veterinary Medicine, University of California, Davis, CA, USA.
- Division of Endocrinology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA.
| | - Colleen M Craig
- Division of Endocrinology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Dan Spielman
- Division of Endocrinology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Samuel S Cushman
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tracey L McLaughlin
- Division of Endocrinology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
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12
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Mahdiani A, Kheirandish M, Bonakdaran S. Correlation Between White Blood Cell Count and Insulin Resistance in Type 2 Diabetes. Curr Diabetes Rev 2019; 15:62-66. [PMID: 29357806 DOI: 10.2174/1573399814666180119143026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/16/2017] [Accepted: 01/09/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND The role of chronic inflammation in insulin resistance states and the pathogenesis of metabolic syndrome, cardiovascular disease and diabetes have been reported earlier. White Blood Cell (WBC) count is an easy marker for estimation of systemic inflammation. OBJECTIVE This study is to clarify whether WBC count is associated with insulin resistance in type 2 diabetic patients. METHODS This cross sectional study was conducted in 283 patients with type 2 diabetes and in 283 healthy non diabetic subjects as control group. Data including: age, gender, blood pressure, height and weight, history of smoking were collected for each patient. Fasting blood sugar, HbA1C, insulin, lipid profiles, creatinine, Urine albumin to creatinine ratio, high sensitive C- reactive protein (HCRP) and WBC was measured for all patients. WBC count was measured in control group. Two groups were compared in WBC count. Insulin resistance was calculated with HOMA-IR formula. Association of WBC count with insulin resistance and metabolic parameters was assessed in diabetic patients. RESULTS WBC count was significantly associated with body mass index, hypertension, and triglyceride level. There was not significant association between WBC count and glycemic index and insulin resistance. CONCLUSION An elevated WBC count (even in the normal range) is closely related to various components of metabolic syndrome but not related to insulin resistance in type 2 diabetes.
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Affiliation(s)
- Armin Mahdiani
- Endocrinology and Metabolism Research Center, Hormozgan University of Medical Science, Bandar Abbas, Iran
| | - Masoume Kheirandish
- Endocrinology and Metabolism Research Center, Hormozgan University of Medical Science, Bandar Abbas, Iran
| | - Shokoufeh Bonakdaran
- Endocrine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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13
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Burhans MS, Hagman DK, Kuzma JN, Schmidt KA, Kratz M. Contribution of Adipose Tissue Inflammation to the Development of Type 2 Diabetes Mellitus. Compr Physiol 2018; 9:1-58. [PMID: 30549014 DOI: 10.1002/cphy.c170040] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The objective of this comprehensive review is to summarize and discuss the available evidence of how adipose tissue inflammation affects insulin sensitivity and glucose tolerance. Low-grade, chronic adipose tissue inflammation is characterized by infiltration of macrophages and other immune cell populations into adipose tissue, and a shift toward more proinflammatory subtypes of leukocytes. The infiltration of proinflammatory cells in adipose tissue is associated with an increased production of key chemokines such as C-C motif chemokine ligand 2, proinflammatory cytokines including tumor necrosis factor α and interleukins 1β and 6 as well as reduced expression of the key insulin-sensitizing adipokine, adiponectin. In both rodent models and humans, adipose tissue inflammation is consistently associated with excess fat mass and insulin resistance. In humans, associations with insulin resistance are stronger and more consistent for inflammation in visceral as opposed to subcutaneous fat. Further, genetic alterations in mouse models of obesity that reduce adipose tissue inflammation are-almost without exception-associated with improved insulin sensitivity. However, a dissociation between adipose tissue inflammation and insulin resistance can be observed in very few rodent models of obesity as well as in humans following bariatric surgery- or low-calorie-diet-induced weight loss, illustrating that the etiology of insulin resistance is multifactorial. Taken together, adipose tissue inflammation is a key factor in the development of insulin resistance and type 2 diabetes in obesity, along with other factors that likely include inflammation and fat accumulation in other metabolically active tissues. © 2019 American Physiological Society. Compr Physiol 9:1-58, 2019.
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Affiliation(s)
- Maggie S Burhans
- Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.,Department of Epidemiology, University of Washington, Seattle, Washington, USA
| | - Derek K Hagman
- Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Jessica N Kuzma
- Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Kelsey A Schmidt
- Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.,Department of Epidemiology, University of Washington, Seattle, Washington, USA
| | - Mario Kratz
- Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.,Department of Epidemiology, University of Washington, Seattle, Washington, USA.,Department of Medicine, University of Washington, Seattle, Washington, USA
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14
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Oliva-Olivera W, Lhamyani S, Coín-Aragüez L, Alcaide-Torres J, Cardona F, El Bekay R, Tinahones FJ. Involvement of acetyl-CoA-producing enzymes in the deterioration of the functional potential of adipose-derived multipotent cells from subjects with metabolic syndrome. Metabolism 2018; 88:12-21. [PMID: 30172756 DOI: 10.1016/j.metabol.2018.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/24/2018] [Accepted: 08/28/2018] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The expansion capacity of white adipose tissue influences the distribution of fat depots in the body, the visceral accumulation of which is linked to metabolic syndrome, regardless of the degree of obesity of the subjects. Alterations in the adipose tissue-derived mesenchymal stem cells (ASCs) may contribute to the adipose tissue remodeling associated with metabolic syndrome and impact the regional distribution of adipose tissue by generating inherently dysfunctional adipocytes. Here we examine the expression levels of acetyl-CoA-producing enzymes and their relationship with the lipogenic, antioxidant and oxidative potential of adipocytes generated from visceral ASCs (adipo-visASCs) and subcutaneous ASCs (adipo-subASCs) from subjects with different metabolic profiles. MATERIALS/METHODS Paired samples of visceral and subcutaneous adipose tissue were processed to isolate the respective ASCs from normal-weight (Nw) subjects and obese patients with metabolic syndrome (METS) and without METS (NonMETS). qPCR was used to quantify the expression levels of the genes studied in both adipo-ASCs from the patient groups and those generated after silencing by small interfering RNA of acetyl-CoA-producing enzymes. The accumulation of lipids was quantified by absorbance. RESULTS No significant differences in cell yield or CD34+CD31-CD45- ASC percentage were observed between the different patient groups. Unlike adipo-visASCs, adipo-subASCs from METS patients showed a decrease in expression levels of acetyl-CoA-producing enzymes as well as proteins linked to lipogenesis, antioxidant defense and fatty acid oxidation. Transcriptional silencing of acetyl-CoA-producing enzymes in adipo-subASCs reduced lipid accumulation and affected transcription levels of lipogenic and antioxidant defense proteins. CONCLUSIONS Adipo-subASCs may be more susceptible than adipo-visASCs to deterioration of the lipogenic, oxidative and antioxidant potential associated with metabolic syndrome. Intrinsic alterations in transcription levels of acetyl-CoA-producing enzymes may contribute to the metabolic reprogramming of adipo-subASCs from METS patients.
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Affiliation(s)
- Wilfredo Oliva-Olivera
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Spain; Pathophysiology of Obesity and Nutrition, CIBEROBN, Institute of Health Carlos III, ISCIII, Spain.
| | - Said Lhamyani
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Spain; Pathophysiology of Obesity and Nutrition, CIBEROBN, Institute of Health Carlos III, ISCIII, Spain
| | - Leticia Coín-Aragüez
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Spain; Pathophysiology of Obesity and Nutrition, CIBEROBN, Institute of Health Carlos III, ISCIII, Spain
| | - Juan Alcaide-Torres
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Spain; Pathophysiology of Obesity and Nutrition, CIBEROBN, Institute of Health Carlos III, ISCIII, Spain
| | - Fernando Cardona
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Spain; Pathophysiology of Obesity and Nutrition, CIBEROBN, Institute of Health Carlos III, ISCIII, Spain
| | - Rajaa El Bekay
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Spain; Pathophysiology of Obesity and Nutrition, CIBEROBN, Institute of Health Carlos III, ISCIII, Spain.
| | - Francisco J Tinahones
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Spain; Pathophysiology of Obesity and Nutrition, CIBEROBN, Institute of Health Carlos III, ISCIII, Spain.
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15
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Abstract
Adipose morphology is defined as the number and size distribution of adipocytes (fat cells) within adipose tissue. Adipose tissue with fewer but larger adipocytes is said to have a 'hypertrophic' morphology, whereas adipose with many adipocytes of a smaller size is said to have a 'hyperplastic' morphology. Hypertrophic adipose morphology is positively associated with insulin resistance, diabetes and cardiovascular disease. By contrast, hyperplastic morphology is associated with improved metabolic parameters. These phenotypic associations suggest that adipose morphology influences risk of cardiometabolic disease. Intriguingly, monozygotic twin studies have determined that adipose morphology is in part determined genetically. Therefore, identifying the genetic regulation of adipose morphology may help us to predict, prevent and ameliorate insulin resistance and associated metabolic diseases. Here, we review the current literature regarding adipose morphology in relation to: (1) metabolic and medical implications; (2) the methods used to assess adipose morphology; and (3) transcriptional differences between morphologies. We further highlight three mechanisms that have been hypothesized to promote adipocyte hypertrophy and thus to regulate adipose morphology.
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Affiliation(s)
- Panna Tandon
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, UK
| | - Rebecca Wafer
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, UK
| | - James E N Minchin
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4TJ, Scotland, UK
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16
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Oliva-Olivera W, Lhamyani S, Coín-Aragüez L, Castellano-Castillo D, Alcaide-Torres J, Yubero-Serrano EM, El Bekay R, Tinahones FJ. Neovascular deterioration, impaired NADPH oxidase and inflammatory cytokine expression in adipose-derived multipotent cells from subjects with metabolic syndrome. Metabolism 2017; 71:132-143. [PMID: 28521866 DOI: 10.1016/j.metabol.2017.03.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/24/2017] [Accepted: 03/23/2017] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Expansion of adipose tissue depends on the growth of its vascular network and it has been shown that adipose tissue dysfunction in obese subjects with the metabolic syndrome is associated with decreased angiogenesis. However, some subjects with a high body mass index do not develop metabolic abnormalities associated with obesity. In this study we examined the neovascular properties, expression levels of proteins involved in cellular redox balance and inflammatory cytokines in adipose-derived multipotent mesenchymal cells (ASCs) of subjects with different metabolic profiles. MATERIALS/METHODS We applied cell culture, flow cytometry, RT-qPCR and ELISA techniques to characterize the ASCs isolated from paired biopsies of visceral (visASCs) and subcutaneous (subASCs) adipose tissue from 39 subjects grouped into normal weight (Nw), obese without metabolic syndrome (NonMS) and with metabolic syndrome (MS). RESULTS VisASCs and subASCs from MS subjects showed a decrease in tubules formation capacity compared to ASCs from NonMS subjects as well as changes in the expression levels of proteins involved in cell redox balance and secretion levels of proteins linked to the senescence-associated secretory phenotype. Deterioration in the neovascular properties of subASCs from the MS subjects was also evident in the decreased levels of VEGF secretion during adipogenesis and in the effects of the conditioned medium on endothelial cell tubule formation. CONCLUSIONS Our findings suggest a redox imbalance status in ASCs from subjects with metabolic syndrome and decreased their neovascular function that probably contributes to the vascular insufficiency of adipose depots.
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Affiliation(s)
- Wilfredo Oliva-Olivera
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Málaga, Spain; CIBER Fisiopatología Obesidad y Nutrición, Instituto de Salud Carlos III, Spain.
| | - Said Lhamyani
- Research Laboratory, Science School, University of Málaga (UMA), Campus Teatinos s/n, 29010 Málaga, Spain
| | - Leticia Coín-Aragüez
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Málaga, Spain; CIBER Fisiopatología Obesidad y Nutrición, Instituto de Salud Carlos III, Spain
| | - Daniel Castellano-Castillo
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Málaga, Spain; CIBER Fisiopatología Obesidad y Nutrición, Instituto de Salud Carlos III, Spain
| | - Juan Alcaide-Torres
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Málaga, Spain; CIBER Fisiopatología Obesidad y Nutrición, Instituto de Salud Carlos III, Spain
| | - Elena María Yubero-Serrano
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Málaga, Spain; Lipids and Atherosclerosis Unit, Maimonides Institute of Biomedical Research of Córdoba, Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| | - Rajaa El Bekay
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Málaga, Spain; CIBER Fisiopatología Obesidad y Nutrición, Instituto de Salud Carlos III, Spain.
| | - Francisco José Tinahones
- Department of Clinical Endocrinology and Nutrition, Institute of Biomedical Research of Málaga (IBIMA), Hospital of Málaga (Virgen de la Victoria), University of Málaga (UMA), Málaga, Spain; CIBER Fisiopatología Obesidad y Nutrición, Instituto de Salud Carlos III, Spain.
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17
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Chabot K, Gauthier MS, Garneau P, Rabasa-Lhoret R. Evolution of subcutaneous adipose tissue fibrosis after bariatric surgery. DIABETES & METABOLISM 2017; 43:125-133. [DOI: 10.1016/j.diabet.2016.10.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/15/2016] [Accepted: 10/16/2016] [Indexed: 10/20/2022]
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18
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4-PBA reverses autophagic dysfunction and improves insulin sensitivity in adipose tissue of obese mice via Akt/mTOR signaling. Biochem Biophys Res Commun 2017; 484:529-535. [PMID: 28153729 DOI: 10.1016/j.bbrc.2017.01.106] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 01/21/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND 4-phenyl butyric acid (4-PBA) has been considered as a key regulator of insulin resistance in obesity. However the mechanism of 4-PBA involved in insulin resistance remains elusive. METHODS We evaluated the effect of 4-PBA on abnormal autophagy and endoplasmic reticulum (ER) stress in obese mice. 4-PBA was administered in obese mice and adipocyte models, and metabolic parameters, autophagy markers, ER stress indicators, Akt/mTOR signaling and insulin signaling molecular were assessed. RESULTS 4-PBA treatment not only reversed autophagic dysfunction and ER stress, but also improved impaired insulin signaling in tunicamycin-induced adipocytes, and 4-PBA also inhibited activated ER stress and elevated insulin sensitivity in adipocytes with Atg7 siRNA. Additionally, administration of 4-PBA improves glucose tolerance and insulin sensitivity in obese mice via regulating abnormal autophagy and ER stress in adipose tissue. The protective effects of 4-PBA were nullified by suppression of Akt and mTOR in adipocytes, suggesting that 4-PBA inhibits autophagy and restores insulin sensitivity via Akt/mTOR signaling partially. CONCLUSIONS 4-PBA reverses autophagic dysfunction and improves insulin sensitivity in adipose tissue of obese mice via Akt/mTOR signaling partly, which could be regarded as novel opportunities for treatment of insulin resistance.
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19
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McLaughlin T, Ackerman SE, Shen L, Engleman E. Role of innate and adaptive immunity in obesity-associated metabolic disease. J Clin Invest 2017; 127:5-13. [PMID: 28045397 DOI: 10.1172/jci88876] [Citation(s) in RCA: 293] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chronic inflammation in adipose tissue, possibly related to adipose cell hypertrophy, hypoxia, and/or intestinal leakage of bacteria and their metabolic products, likely plays a critical role in the development of obesity-associated insulin resistance (IR). Cells of both the innate and adaptive immune system residing in adipose tissues, as well as in the intestine, participate in this process. Thus, M1 macrophages, IFN-γ-secreting Th1 cells, CD8+ T cells, and B cells promote IR, in part through secretion of proinflammatory cytokines. Conversely, eosinophils, Th2 T cells, type 2 innate lymphoid cells, and possibly Foxp3+ Tregs protect against IR through local control of inflammation.
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20
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Kratz M, Hagman DK, Kuzma JN, Foster-Schubert KE, Chan CP, Stewart S, van Yserloo B, Westbrook EO, Arterburn DE, Flum DR, Cummings DE. Improvements in glycemic control after gastric bypass occur despite persistent adipose tissue inflammation. Obesity (Silver Spring) 2016; 24:1438-45. [PMID: 27228052 PMCID: PMC4925247 DOI: 10.1002/oby.21524] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/18/2016] [Accepted: 03/02/2016] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Type 2 diabetes commonly goes into remission following Roux-en-Y gastric bypass (RYGB). As the mechanisms remain incompletely understood, a reduction in adipose tissue inflammation may contribute to these metabolic improvements. Therefore, whether RYGB reduces adipose tissue inflammation compared with equivalent weight loss from an intensive lifestyle intervention was investigated. METHODS Sixteen people with obesity and type 2 diabetes were randomized to RYGB or lifestyle intervention. Fasting blood and subcutaneous abdominal adipose tissue were obtained before and after the loss of ∼7% of baseline weight. Adipose tissue inflammation was assessed by whole-tissue gene expression and flow cytometry-based quantification of tissue leukocytes. RESULTS At 7% weight loss, insulin and metformin use were reduced among the RYGB but not the Lifestyle cohort, while fasting glucose and insulin declined in both. Adipose tissue inflammation increased modestly after RYGB and to a similar extent following nonsurgical weight loss. In both groups, the number of neutrophils increased severalfold (P < 0.001), mRNA levels of the proinflammatory cytokine interleukin-1β increased (P = 0.037), and mRNA expression of the anti-inflammatory and insulin-sensitizing adipokine adiponectin decreased (P = 0.010). CONCLUSIONS A reduction in adipose tissue inflammation is not one of the acute weight loss-independent mechanisms through which RYGB exerts its antidiabetes effects.
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Affiliation(s)
- Mario Kratz
- Division of Public Health Sciences, Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, WA
- Department of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington, Seattle, WA
- Department of Epidemiology, University of Washington, Seattle, WA
- Corresponding author and person to whom reprint requests should be addressed: Mario Kratz, PhD, Fred Hutchinson Cancer Research Center, Cancer Prevention Program M4-B402, 1100 Fairview Ave N, Seattle, WA 98109 USA, Phone: (206) 667-7362, Fax: (206) 667-7850,
| | - Derek K. Hagman
- Division of Public Health Sciences, Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Jessica N. Kuzma
- Division of Public Health Sciences, Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Karen E. Foster-Schubert
- Department of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington, Seattle, WA
| | - Chun P. Chan
- Department of Surgery, University of Washington, Seattle, WA
| | - Skye Stewart
- Department of Surgery, University of Washington, Seattle, WA
| | - Brian van Yserloo
- Diabetes Research Center, Virus Vector and Transgenic Mouse Core, University of Washington, Seattle, WA
| | | | | | - David R. Flum
- Department of Epidemiology, University of Washington, Seattle, WA
- Department of Surgery, University of Washington, Seattle, WA
| | - David E. Cummings
- Department of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington, Seattle, WA
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21
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Lawler HM, Underkofler CM, Kern PA, Erickson C, Bredbeck B, Rasouli N. Adipose Tissue Hypoxia, Inflammation, and Fibrosis in Obese Insulin-Sensitive and Obese Insulin-Resistant Subjects. J Clin Endocrinol Metab 2016; 101:1422-8. [PMID: 26871994 PMCID: PMC4880157 DOI: 10.1210/jc.2015-4125] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/10/2016] [Indexed: 12/19/2022]
Abstract
CONTEXT A substantial number of obese individuals are relatively insulin sensitive and the etiology for this variation remains unknown. OBJECTIVE The primary objective was to detect factors in adipose tissue differentiating obese insulin-sensitive (OBIS) from obese insulin-resistant (OBIR) individuals and investigate whether adipose tissue hypoxia is a contributing factor in the pathogenesis of insulin resistance. DESIGN AND SETTING This was a cross-sectional study in the general community. PARTICIPANTS Subjects consisted of nondiabetic OBIS and OBIR subjects with similar body mass index, age, and total body fat but different insulin sensitivity index as well as lean insulin-sensitive subjects. INTERVENTIONS(S) There were no interventions. MAIN OUTCOME MEASURE(S) We examined adipocytokines and the expression of candidate genes regulating hypoxia, inflammation, and lipogenesis in adipose tissue and adipose tissue oxygenation. RESULTS OBIS subjects had increased plasma adiponectin but similar plasma TNFα and leptin levels as compared with OBIR subjects. Genes regulating inflammation (CD68, MCP1, scavenger receptor A, and oxidized LDL receptor 1) were increased by 40%–60% (P < .05) in OBIR vs OBIS cohorts. In addition, genes involved in extracellular matrix formation such as collagen VI and MMP7 were up-regulated by 43% and 78% (P < .05), respectively, in OBIR vs OBIS. The expression of HIF1α and VEGF gene expression was increased by 37% and 52%, respectively, in OBIR vs OBIS (P < .01). Despite the differential expression in hypoxia-related genes, adipose tissue oxygenation measured by a Licox oxygen probe was not different between OBIS and OBIR subjects, but it was higher in lean subjects as compared with obese subjects. CONCLUSIONS We confirmed that adipose tissue inflammation and fibrosis play an important role in the pathogenesis of insulin resistance independent of obesity in humans. Whether hypoxia is simply a consequence of adipose tissue expansion or is related to the pathogenesis of obesity-induced insulin resistance is yet to be understood.
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Affiliation(s)
- Helen M Lawler
- Division of Endocrinology, Metabolism, and Diabetes (H.M.L., C.M.U., C.E., B.B., N.R.), University of Colorado, School of Medicine, Aurora, Colorado 80045; University of Kentucky and the Barnstable Brown Diabetes and Obesity Center (P.A.K.), Lexington, Kentucky 40536; and Veterans Affairs Eastern Colorado Health Care System (N.R.), Denver, Colorado 80262
| | - Chantal M Underkofler
- Division of Endocrinology, Metabolism, and Diabetes (H.M.L., C.M.U., C.E., B.B., N.R.), University of Colorado, School of Medicine, Aurora, Colorado 80045; University of Kentucky and the Barnstable Brown Diabetes and Obesity Center (P.A.K.), Lexington, Kentucky 40536; and Veterans Affairs Eastern Colorado Health Care System (N.R.), Denver, Colorado 80262
| | - Philip A Kern
- Division of Endocrinology, Metabolism, and Diabetes (H.M.L., C.M.U., C.E., B.B., N.R.), University of Colorado, School of Medicine, Aurora, Colorado 80045; University of Kentucky and the Barnstable Brown Diabetes and Obesity Center (P.A.K.), Lexington, Kentucky 40536; and Veterans Affairs Eastern Colorado Health Care System (N.R.), Denver, Colorado 80262
| | - Christopher Erickson
- Division of Endocrinology, Metabolism, and Diabetes (H.M.L., C.M.U., C.E., B.B., N.R.), University of Colorado, School of Medicine, Aurora, Colorado 80045; University of Kentucky and the Barnstable Brown Diabetes and Obesity Center (P.A.K.), Lexington, Kentucky 40536; and Veterans Affairs Eastern Colorado Health Care System (N.R.), Denver, Colorado 80262
| | - Brooke Bredbeck
- Division of Endocrinology, Metabolism, and Diabetes (H.M.L., C.M.U., C.E., B.B., N.R.), University of Colorado, School of Medicine, Aurora, Colorado 80045; University of Kentucky and the Barnstable Brown Diabetes and Obesity Center (P.A.K.), Lexington, Kentucky 40536; and Veterans Affairs Eastern Colorado Health Care System (N.R.), Denver, Colorado 80262
| | - Neda Rasouli
- Division of Endocrinology, Metabolism, and Diabetes (H.M.L., C.M.U., C.E., B.B., N.R.), University of Colorado, School of Medicine, Aurora, Colorado 80045; University of Kentucky and the Barnstable Brown Diabetes and Obesity Center (P.A.K.), Lexington, Kentucky 40536; and Veterans Affairs Eastern Colorado Health Care System (N.R.), Denver, Colorado 80262
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22
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Dam V, Sikder T, Santosa S. From neutrophils to macrophages: differences in regional adipose tissue depots. Obes Rev 2016; 17:1-17. [PMID: 26667065 DOI: 10.1111/obr.12335] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 09/01/2015] [Accepted: 09/23/2015] [Indexed: 12/27/2022]
Abstract
Currently, we do not fully understand the underlying mechanisms of how regional adiposity promotes metabolic dysregulation. As adipose tissue expands, there is an increase in chronic systemic low-grade inflammation due to greater infiltration of immune cells and production of cytokines. This chronic inflammation is thought to play a major role in the development of metabolic complications and disease such as insulin resistance and diabetes. We know that different adipose tissue depots contribute differently to the risk of metabolic disease. People who have an upper body fat distribution around the abdomen are at greater risk of disease than those who tend to store fat in their lower body around the hips and thighs. Thus, it is conceivable that adipose tissue depots contribute differently to the inflammatory milieu as a result of varied infiltration of immune cell types. In this review, we describe the role and function of major resident immune cells in the development of adipose tissue inflammation and discuss their regional differences in the context of metabolic disease risk. We find that although initial studies have found regional differences, a more comprehensive understanding of how immune cells interrupt adipose tissue homeostasis is needed.
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Affiliation(s)
- V Dam
- Department of Exercise Science, Concordia University, Montreal, QC, Canada.,Nutrition, Obesity, and Metabolism Lab, PERFORM Centre, Concordia University, Montreal, QC, Canada
| | - T Sikder
- Department of Exercise Science, Concordia University, Montreal, QC, Canada.,Nutrition, Obesity, and Metabolism Lab, PERFORM Centre, Concordia University, Montreal, QC, Canada
| | - S Santosa
- Department of Exercise Science, Concordia University, Montreal, QC, Canada.,Nutrition, Obesity, and Metabolism Lab, PERFORM Centre, Concordia University, Montreal, QC, Canada
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Perbellini F, Gomes RSM, Vieira S, Buchanan D, Malandraki-Miller S, Bruyneel AAN, Sousa Fialho MDL, Ball V, Clarke K, Faggian G, Carr CA. Chronic High-Fat Feeding Affects the Mesenchymal Cell Population Expanded From Adipose Tissue but Not Cardiac Atria. Stem Cells Transl Med 2015; 4:1403-14. [PMID: 26518239 DOI: 10.5966/sctm.2015-0024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 09/14/2015] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Mesenchymal stem cells offer a promising approach to the treatment of myocardial infarction and prevention of heart failure. However, in the clinic, cells will be isolated from patients who may be suffering from comorbidities such as obesity and diabetes, which are known to adversely affect progenitor cells. Here we determined the effect of a high-fat diet (HFD) on mesenchymal stem cells from cardiac and adipose tissues. Mice were fed a HFD for 4 months, after which cardiosphere-derived cells (CDCs) were cultured from atrial tissue and adipose-derived mesenchymal cells (ADMSCs) were isolated from epididymal fat depots. HFD raised body weight, fasted plasma glucose, lactate, and insulin. Ventricle and liver tissue of HFD-fed mice showed protein changes associated with an early type 2 diabetic phenotype. At early passages, more ADMSCs were obtained from HFD-fed mice than from chow-fed mice, whereas CDC number was not affected by HFD. Migratory and clonogenic capacity and release of vascular endothelial growth factor did not differ between cells from HFD- and chow-fed animals. CDCs from chow-fed and HFD-fed mice showed no differences in surface marker expression, whereas ADMSCs from HFD-fed mice contained more cells positive for CD105, DDR2, and CD45, suggesting a high component of endothelial, fibroblast, and hematopoietic cells. Both Noggin and transforming growth factor β-supplemented medium induced an early stage of differentiation in CDCs toward the cardiomyocyte phenotype. Thus, although chronic high-fat feeding increased the number of fibroblasts and hematopoietic cells within the ADMSC population, it left cardiac progenitor cells largely unaffected. SIGNIFICANCE Mesenchymal cells are a promising candidate cell source for restoring lost tissue and thereby preventing heart failure. In the clinic, cells are isolated from patients who may be suffering from comorbidities such as obesity and diabetes. This study examined the effect of a high-fat diet on mesenchymal cells from cardiac and adipose tissues. It was demonstrated that a high-fat diet did not affect cardiac progenitor cells but increased the number of fibroblasts and hematopoietic cells within the adipose-derived mesenchymal cell population.
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Affiliation(s)
- Filippo Perbellini
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom Department of Cardiac Surgery, University of Verona,Verona, Italy
| | - Renata S M Gomes
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Silvia Vieira
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Dougal Buchanan
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Arne A N Bruyneel
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Vicky Ball
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Kieran Clarke
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Giuseppe Faggian
- Department of Cardiac Surgery, University of Verona,Verona, Italy
| | - Carolyn A Carr
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Tencerová M, Kračmerová J, Krauzová E, Mališová L, Kováčová Z, Wedellová Z, Šiklová M, Štich V, Rossmeislová L. Experimental hyperglycemia induces an increase of monocyte and T-lymphocyte content in adipose tissue of healthy obese women. PLoS One 2015; 10:e0122872. [PMID: 25894202 PMCID: PMC4403863 DOI: 10.1371/journal.pone.0122872] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/24/2015] [Indexed: 01/04/2023] Open
Abstract
Background/Objectives Hyperglycemia represents one of possible mediators for activation of immune system and may contribute to worsening of inflammatory state associated with obesity. The aim of our study was to investigate the effect of a short-term hyperglycemia (HG) on the phenotype and relative content of immune cells in circulation and subcutaneous abdominal adipose tissue (SAAT) in obese women without metabolic complications. Subjects/Methods Three hour HG clamp with infusion of octreotide and control investigations with infusion of octreotide or saline were performed in three groups of obese women (Group1: HG, Group 2: Octreotide, Group 3: Saline, n=10 per group). Before and at the end of the interventions, samples of SAAT and blood were obtained. The relative content of immune cells in blood and SAAT was determined by flow cytometry. Gene expression analysis of immunity-related markers in SAAT was performed by quantitative real-time PCR. Results In blood, no changes in analysed immune cell population were observed in response to HG. In SAAT, HG induced an increase in the content of CD206 negative monocytes/macrophages (p<0.05) and T lymphocytes (both T helper and T cytotoxic lymphocytes, p<0.01). Further, HG promoted an increase of mRNA levels of immune response markers (CCL2, TLR4, TNFα) and lymphocyte markers (CD3g, CD4, CD8a, TBX21, GATA3, FoxP3) in SAAT (p<0.05 and 0.01). Under both control infusions, none of these changes were observed. Conclusions Acute HG significantly increased the content of monocytes and lymphocytes in SAAT of healthy obese women. This result suggests that the short-term HG can modulate an immune status of AT in obese subjects.
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Affiliation(s)
- Michaela Tencerová
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
- * E-mail:
| | - Jana Kračmerová
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
| | - Eva Krauzová
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
| | - Lucia Mališová
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
| | - Zuzana Kováčová
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
| | - Zuzana Wedellová
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
- Second Internal Medicine Department, Vinohrady Teaching Hospital, Prague, Czech Republic
| | - Michaela Šiklová
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
| | - Vladimir Štich
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
| | - Lenka Rossmeislová
- Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Charles University in Prague, Prague 10, CZ-100 00 Czech Republic
- Department of Sport Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, CZ-100 00 Czech Republic
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25
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Abstract
Obesity-associated insulin resistance, a common precursor of type 2 diabetes, is characterized by chronic inflammation of tissues, including visceral adipose tissue (VAT). Here we show that B-1a cells, a subpopulation of B lymphocytes, are novel and important regulators of this process. B-1a cells are reduced in frequency in obese high-fat diet (HFD)-fed mice, and EGFP interleukin-10 (IL-10) reporter mice show marked reductions in anti-inflammatory IL-10 production by B cells in vivo during obesity. In VAT, B-1a cells are the dominant producers of B cell-derived IL-10, contributing nearly half of the expressed IL-10 in vivo. Adoptive transfer of B-1a cells into HFD-fed B cell-deficient mice rapidly improves insulin resistance and glucose tolerance through IL-10 and polyclonal IgM-dependent mechanisms, whereas transfer of B-2 cells worsens metabolic disease. Genetic knockdown of B cell-activating factor (BAFF) in HFD-fed mice or treatment with a B-2 cell-depleting, B-1a cell-sparing anti-BAFF antibody attenuates insulin resistance. These findings establish B-1a cells as a new class of immune regulators that maintain metabolic homeostasis and suggest manipulation of these cells as a potential therapy for insulin resistance.
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Affiliation(s)
- Lei Shen
- Shanghai Institute of Immunology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | | | - Michael N Alonso
- Department of Pathology, Stanford University School of Medicine, Stanford, CA
| | - Robert Yuan
- Department of Pathology, Stanford University School of Medicine, Stanford, CA
| | - Daniel A Winer
- Division of Cellular & Molecular Biology, Diabetes Research Group, Toronto General Research Institute (TGRI), University Health Network, Toronto, Ontario, Canada
| | - Edgar G Engleman
- Department of Pathology, Stanford University School of Medicine, Stanford, CA
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26
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Wang Z, Lee Y, Eun JS, Bae EJ. Inhibition of adipocyte inflammation and macrophage chemotaxis by butein. Eur J Pharmacol 2014; 738:40-8. [DOI: 10.1016/j.ejphar.2014.05.031] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/01/2014] [Accepted: 05/14/2014] [Indexed: 01/27/2023]
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27
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Bushnell C, McCullough LD, Awad IA, Chireau MV, Fedder WN, Furie KL, Howard VJ, Lichtman JH, Lisabeth LD, Piña IL, Reeves MJ, Rexrode KM, Saposnik G, Singh V, Towfighi A, Vaccarino V, Walters MR. Guidelines for the prevention of stroke in women: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2014; 45:1545-88. [PMID: 24503673 PMCID: PMC10152977 DOI: 10.1161/01.str.0000442009.06663.48] [Citation(s) in RCA: 627] [Impact Index Per Article: 62.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The aim of this statement is to summarize data on stroke risk factors that are unique to and more common in women than men and to expand on the data provided in prior stroke guidelines and cardiovascular prevention guidelines for women. This guideline focuses on the risk factors unique to women, such as reproductive factors, and those that are more common in women, including migraine with aura, obesity, metabolic syndrome, and atrial fibrillation. METHODS Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council's Scientific Statement Oversight Committee and the AHA's Manuscript Oversight Committee. The panel reviewed relevant articles on adults using computerized searches of the medical literature through May 15, 2013. The evidence is organized within the context of the AHA framework and is classified according to the joint AHA/American College of Cardiology and supplementary AHA Stroke Council methods of classifying the level of certainty and the class and level of evidence. The document underwent extensive AHA internal peer review, Stroke Council Leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the AHA Science Advisory and Coordinating Committee. RESULTS We provide current evidence, research gaps, and recommendations on risk of stroke related to preeclampsia, oral contraceptives, menopause, and hormone replacement, as well as those risk factors more common in women, such as obesity/metabolic syndrome, atrial fibrillation, and migraine with aura. CONCLUSIONS To more accurately reflect the risk of stroke in women across the lifespan, as well as the clear gaps in current risk scores, we believe a female-specific stroke risk score is warranted.
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28
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Li H, Zhou B, Xu L, Liu J, Zang W, Wu S, Sun H. The reciprocal interaction between autophagic dysfunction and ER stress in adipose insulin resistance. Cell Cycle 2013; 13:565-79. [DOI: 10.4161/cc.27406] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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29
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Jansen HJ, Vervoort GM, van der Graaf M, Stienstra R, Tack CJ. Liver fat content is linked to inflammatory changes in subcutaneous adipose tissue in type 2 diabetes patients. Clin Endocrinol (Oxf) 2013; 79:661-6. [PMID: 23167778 DOI: 10.1111/cen.12105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 10/28/2012] [Accepted: 11/11/2012] [Indexed: 12/14/2022]
Abstract
BACKGROUND Patients with type 2 diabetes mellitus (T2DM) are typically overweight and have an increased liver fat content (LFAT). High LFAT may be explained by an increased efflux of free fatty acids from the adipose tissue, which is partly instigated by inflammatory changes. This would imply an association between inflammatory features of the adipose tissue and liver fat content. OBJECTIVE To analyse associations between inflammatory features of the adipose tissue and liver fat content. DESIGN A cross-sectional study. PATIENTS Twenty-seven obese patients with insulin-treated T2DM were studied. MEASUREMENTS LFAT content was measured by proton magnetic resonance spectroscopy. A subcutaneous (sc) fat biopsy was obtained to determine morphology and protein levels within adipose tissue. In addition to fat cell size, the percentage of macrophages and the presence of crown-like structures (CLSs) within sc fat were assessed by CD68-immunohistochemical staining. RESULTS Mean LFAT percentage was 11·1 ± 1·7% (range: 0·75-32·9%); 63% of the patients were diagnosed with an elevated LFAT (upper range of normal ≤5·5%). Whereas adipocyte size did not correlate with LFAT, 3 of 4 subjects with CLSs in sc fat had elevated LFAT and the percentage of macrophages present in sc adipose tissue was positively associated with LFAT. Protein concentrations of adiponectin within adipose tissue negatively correlated with LFAT. Adipose tissue protein levels of the key inflammatory adipokine plasminogen activator inhibitor-1 (PAI-1) were positively associated with LFAT. CONCLUSIONS Several pro-inflammatory changes in sc adipose tissue associate with increased LFAT content in obese insulin-treated patients with T2DM. These findings suggest that inflammatory changes at the level of the adipose tissue may drive liver fat accumulation.
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Affiliation(s)
- Henry J Jansen
- Department of Internal Medicine, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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30
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Mukhtar NA, Bacchetti P, Ayala CE, Melgar J, Christensen S, Maher JJ, Khalili M. Insulin sensitivity and variability in hepatitis C virus infection using direct measurement. Dig Dis Sci 2013; 58:1141-8. [PMID: 23086116 PMCID: PMC3566265 DOI: 10.1007/s10620-012-2438-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Accepted: 09/26/2012] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND AIMS Studies investigating insulin resistance (IR) in chronic hepatitis C virus (HCV) infection have used surrogate measures of IR that have limited reliability. We aimed to describe the distribution and risk factors associated with IR and its change over time in HCV using direct measurement. METHODS One hundred two non-cirrhotic, non-diabetic, HCV-infected subjects underwent clinical, histologic, and metabolic evaluation, and 27 completed repeat evaluation at 6 months. Insulin-mediated glucose uptake was measured by steady-state plasma glucose (SSPG) concentration during the insulin suppression test. RESULTS Three subjects with diabetes were excluded and 95 completed all testing. SSPG ranged from 39 to 328 mg/dL (mean 135 mg/dL) and was stable over time (mean SSPG change -0.3 mg/dL). SSPG was associated with Latino ethnicity (Coef 67, 95 % CI 37-96), BMI (Coef 19 per 5 kg/m(2), 95 % CI 5-32), ferritin (Coef 1.4 per 10 ng/ml, 95 % CI 0.2-2.5), male gender (Coef -48, 95 % CI -80 to -16), and HDL (Coef -16, 95 % CI -28 to -5 mg/dL). Current tobacco use (Coef 55, 95 % CI 19-90), steatosis (Coef -44, 95 % CI -86 to -3), and increases in BMI (Coef 30 per 5 kg/m(2), 95 % CI 6-53) and triglyceride (Coef 3.5 per 10 mg/dL, 95 % CI 0.3-6.7) predicted change in SSPG. CONCLUSIONS There was a wide spectrum of insulin resistance in our HCV population. Host factors, rather than viral factors, appeared to more greatly influence insulin action and its change in HCV.
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Affiliation(s)
- Nizar A. Mukhtar
- Department of Medicine, University of California San Francisco, San Francisco, CA
| | - Peter Bacchetti
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA
| | - Claudia E Ayala
- Department of Medicine, University of California San Francisco, San Francisco, CA
| | - Jennifer Melgar
- Department of Medicine, University of California San Francisco, San Francisco, CA
| | - Spencer Christensen
- Department of Medicine, University of California San Francisco, San Francisco, CA
| | - Jacquelyn J. Maher
- Department of Medicine, University of California San Francisco, San Francisco, CA,Liver Center, University of California San Francisco, San Francisco, CA
| | - Mandana Khalili
- Department of Medicine, University of California San Francisco, San Francisco, CA,Liver Center, University of California San Francisco, San Francisco, CA
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31
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Qatanani M, Tan Y, Dobrin R, Greenawalt DM, Hu G, Zhao W, Olefsky JM, Sears DD, Kaplan LM, Kemp DM. Inverse regulation of inflammation and mitochondrial function in adipose tissue defines extreme insulin sensitivity in morbidly obese patients. Diabetes 2013; 62:855-63. [PMID: 23223024 PMCID: PMC3581230 DOI: 10.2337/db12-0399] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Obesity is associated with insulin resistance, a major risk factor for type 2 diabetes and cardiovascular disease. However, not all obese individuals are insulin resistant, which confounds our understanding of the mechanistic link between these conditions. We conducted transcriptome analyses on 835 obese subjects with mean BMI of 48.8, on which we have previously reported genetic associations of gene expression. Here, we selected ~320 nondiabetic (HbA(1c) <7.0) subjects and further stratified the cohort into insulin-resistant versus insulin-sensitive subgroups based on homeostasis model assessment-insulin resistance. An unsupervised informatics analysis revealed that immune response and inflammation-related genes were significantly downregulated in the omental adipose tissue of obese individuals with extreme insulin sensitivity and, to a much lesser extent, in subcutaneous adipose tissue. In contrast, genes related to β-oxidation and the citric acid cycle were relatively overexpressed in adipose of insulin-sensitive patients. These observations were verified by querying an independent cohort of our published dataset of 37 subjects whose subcutaneous adipose tissue was sampled before and after treatment with thiazolidinediones. Whereas the immune response and inflammation pathway genes were downregulated by thiazolidinedione treatment, β-oxidation and citric acid cycle genes were upregulated. This work highlights the critical role that omental adipose inflammatory pathways might play in the pathophysiology of insulin resistance, independent of body weight.
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MESH Headings
- Adult
- Biopsy
- Body Mass Index
- Citric Acid Cycle/drug effects
- Cohort Studies
- Diabetes Mellitus, Type 2/complications
- Gene Expression Profiling
- Gene Expression Regulation, Enzymologic/drug effects
- Humans
- Hypoglycemic Agents/therapeutic use
- Insulin Resistance
- Intra-Abdominal Fat/drug effects
- Intra-Abdominal Fat/immunology
- Intra-Abdominal Fat/metabolism
- Intra-Abdominal Fat/pathology
- Mitochondria/drug effects
- Mitochondria/metabolism
- Mitochondria/pathology
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Obesity, Morbid/complications
- Obesity, Morbid/immunology
- Obesity, Morbid/metabolism
- Obesity, Morbid/pathology
- Oligonucleotide Array Sequence Analysis
- Oxidative Phosphorylation/drug effects
- RNA, Messenger/metabolism
- Subcutaneous Fat, Abdominal/drug effects
- Subcutaneous Fat, Abdominal/immunology
- Subcutaneous Fat, Abdominal/metabolism
- Subcutaneous Fat, Abdominal/pathology
- Thiazolidinediones/therapeutic use
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Affiliation(s)
- Mohammed Qatanani
- Discovery and Preclinical Sciences, Merck Research Laboratories, Rahway, New Jersey
- Diabetes and Endocrinology, Merck Research Laboratories, Rahway, New Jersey
| | - Yejun Tan
- Discovery and Preclinical Sciences, Merck Research Laboratories, Rahway, New Jersey
- Informatics and Analysis, Merck Research Laboratories, Rahway, New Jersey
| | - Radu Dobrin
- Discovery and Preclinical Sciences, Merck Research Laboratories, Rahway, New Jersey
- Informatics and Analysis, Merck Research Laboratories, Rahway, New Jersey
| | - Danielle M. Greenawalt
- Discovery and Preclinical Sciences, Merck Research Laboratories, Rahway, New Jersey
- Informatics and Analysis, Merck Research Laboratories, Rahway, New Jersey
| | - Guanghui Hu
- Discovery and Preclinical Sciences, Merck Research Laboratories, Rahway, New Jersey
- Informatics and Analysis, Merck Research Laboratories, Rahway, New Jersey
| | - Wenqing Zhao
- Discovery and Preclinical Sciences, Merck Research Laboratories, Rahway, New Jersey
- Informatics and Analysis, Merck Research Laboratories, Rahway, New Jersey
| | - Jerrold M. Olefsky
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, California
| | - Dorothy D. Sears
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, California
| | - Lee M. Kaplan
- Gastrointestinal Metabolism Laboratory, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Daniel M. Kemp
- Discovery and Preclinical Sciences, Merck Research Laboratories, Rahway, New Jersey
- Diabetes and Endocrinology, Merck Research Laboratories, Rahway, New Jersey
- Corresponding author: Daniel M. Kemp,
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32
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Goedecke JH, Levitt NS, Evans J, Ellman N, Hume DJ, Kotze L, Tootla M, Victor H, Keswell D. The role of adipose tissue in insulin resistance in women of African ancestry. J Obes 2013; 2013:952916. [PMID: 23401754 PMCID: PMC3557633 DOI: 10.1155/2013/952916] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 12/13/2012] [Indexed: 01/01/2023] Open
Abstract
Women of African ancestry, particularly those living in industrialized countries, experience a disproportionately higher prevalence of type 2 diabetes (T2D) compared to their white counterparts. Similarly, obesity and insulin resistance, which are major risk factors for T2D, are greater in black compared to white women. The exact mechanisms underlying these phenomena are not known. This paper will focus on the role of adipose tissue biology. Firstly, the characteristic body fat distribution of women of African ancestry will be discussed, followed by the depot-specific associations with insulin resistance. Factors involved in adipose tissue biology and their relation to insulin sensitivity will then be explored, including the role of sex hormones, glucocorticoid metabolism, lipolysis and adipogenesis, and their consequent effects on adipose tissue hypoxia, oxidative stress, and inflammation. Finally the role of ectopic fat deposition will be discussed. The paper proposes directions for future research, in particular highlighting the need for longitudinal and/or intervention studies to better understand the mechanisms underlying the high prevalence of insulin resistance and T2D in women of African ancestry.
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Affiliation(s)
- Julia H Goedecke
- UCT/MRC Research Unit for Exercise Science and Sports Medicine, South African Medical Research Council, Parow, Cape Town 7505, South Africa.
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33
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McLaughlin T. Metabolic heterogeneity of obesity: role of adipose tissue. INTERNATIONAL JOURNAL OF OBESITY SUPPLEMENTS 2012; 2:S8-S10. [PMID: 25089194 PMCID: PMC4109083 DOI: 10.1038/ijosup.2012.3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Obesity is not synonymous with insulin resistance. Why some but not all individuals develop insulin resistance with weight excess is not clear, but a number of plausible hypotheses with ample support now exist. This article reviews regional fat distribution, inflammation, lipotoxicity/ectopic fat and impaired adipogenesis as leading theories as to why excess body weight has the potential to promote insulin resistance.
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Affiliation(s)
- T McLaughlin
- Division of Endocrinology, Stanford University School of Medicine , Stanford, CA, USA
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34
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Mukhtar NA, Ayala C, Maher JJ, Khalili M. Assessment of factors associated with pre-diabetes in HCV infection including direct and dynamic measurements of insulin action. J Viral Hepat 2012; 19:480-7. [PMID: 22676360 PMCID: PMC3375865 DOI: 10.1111/j.1365-2893.2011.01568.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although hepatitis C (HCV) is associated with diabetes, few studies have examined pre-diabetes in this population. We aimed to evaluate factors associated with pre-diabetes in HCV-infected patients, including direct measurement of insulin action. Ninety-seven non-cirrhotic, non-diabetic and HCV-infected patients underwent clinical evaluation and oral glucose tolerance testing (OGTT). Insulin sensitivity was measured directly by steady-state plasma glucose (SSPG) concentration during insulin suppression test. Early phase and total insulin secretion were determined using OGTT. Rates of pre-diabetes were as follows: 21% impaired fasting glucose (IFG), 7% impaired glucose tolerance (IGT) and 9% combined IFG/IGT. Twelve percent of Caucasians, 50% of African Americans and 70% of Latinos had pre-diabetes (P = 0.002). Patient characteristics among the glucose metabolism categories were similar except those with combined IFG/IGT had a higher body mass index (BMI) vs normal glucose tolerance (NGT) (30 vs 26 kg/m(2), P = 0.007) and lower LDL vs NGT and IGT (74, 104 and 112 mg/dL, respectively, P ≤ 0.01). On multivariable analysis, non-Caucasian race (OR 23.1, P = 0.003), BMI (OR 3.4, P = 0.02) and greater liver inflammation (OR 7.9, P = 0.03) predicted IFG, whereas non-Caucasian race (OR 14.8, P = 0.01) and SSPG (OR 1.1 per 10 units, P = 0.01) predicted IGT. Early and total insulin secretion adjusted for the degree of insulin resistance was decreased in pre-diabetes compared with NGT (P = 0.01 and P = 0.02, respectively). Pre-diabetes is highly prevalent among HCV-infected patients, and in some instances, coincides with host responses to the virus. In most cases, however, factors that are associated with pre-diabetes in HCV-infected patients are similar to those observed in the non-HCV population.
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Affiliation(s)
- Nizar A. Mukhtar
- Department of Medicine, University of California San Francisco, San Francisco, CA
| | - Claudia Ayala
- Department of Medicine, University of California San Francisco, San Francisco, CA
| | - Jacquelyn J. Maher
- Department of Medicine, University of California San Francisco, San Francisco, CA,Liver Center, University of California San Francisco, San Francisco, CA
| | - Mandana Khalili
- Department of Medicine, University of California San Francisco, San Francisco, CA,Liver Center, University of California San Francisco, San Francisco, CA
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35
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Abstract
Adipose cells are unique in the dynamism of their sizes, a requisite for their main function of storing and releasing lipid. Lipid metabolism is crucial for energy homeostasis. However, the regulation of lipid storage capacity in conditions of energy excess and scarcity is still not clear. It is not technically feasible to monitor every process affecting storage capacity such as recruitment, growth/shrinkage and death of individual adipose cells in real time for a sufficiently long period. However, recent computational approaches have allowed an examination of the detailed dynamics of adipose cells using statistical information in the form of precise measurements of adipose cell-size probability distributions. One interesting finding is that the growth/shrinkage of adipose cells (> 50 μm diameter) under positive/negative energy balance is proportional to the surface area of cells, limiting efficient lipid absorption/release from larger adipose cells. In addition to the physical characteristics of adipose cells, quantitative modeling integrates dynamics of adipose cells, providing the mechanism of cell turnover under normal and drug-treated conditions. Thus, further use of mathematical modeling applied to experimental measurements of adipose cell-size probability distributions in conjunction with physiological measurements of metabolic state may help unravel the intricate network of interactions underlying metabolic syndromes in obesity.
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Kelley DS, Adkins Y, Woodhouse LR, Swislocki A, Mackey BE, Siegel D. Docosahexaenoic Acid Supplementation Improved Lipocentric but Not Glucocentric Markers of Insulin Sensitivity in Hypertriglyceridemic Men. Metab Syndr Relat Disord 2012; 10:32-8. [DOI: 10.1089/met.2011.0081] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Darshan S. Kelley
- Western Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, and Department of Nutrition, University of California, Davis, California
| | - Yuriko Adkins
- Western Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, and Department of Nutrition, University of California, Davis, California
| | - Leslie R. Woodhouse
- Western Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, and Department of Nutrition, University of California, Davis, California
| | - Arthur Swislocki
- Veteran Affairs Northern California Health Care System, Martinez, California
- Department of Medicine, School of Medicine, University of California Davis, Sacramento, California
| | - Bruce E. Mackey
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California
| | - David Siegel
- Department of Medicine, School of Medicine, University of California Davis, Sacramento, California
- Veteran Affairs Northern California Health Care System, Sacramento, California
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Dewell A, Marvasti FF, Harris WS, Tsao P, Gardner CD. Low- and high-dose plant and marine (n-3) fatty acids do not affect plasma inflammatory markers in adults with metabolic syndrome. J Nutr 2011; 141:2166-71. [PMID: 22031659 PMCID: PMC3223874 DOI: 10.3945/jn.111.142240] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Chronic inflammation is considered to play a role in the development of cardiovascular disease. Various (n-3) fatty acids (FA) have been reported to have antiinflammatory effects, but there is a lack of consensus in this area, particularly in regard to optimal source(s) and dose(s). This study aimed to determine the effects of high and low doses of (n-3) FA from plant and marine sources on plasma inflammatory marker concentrations. One-hundred adults with metabolic syndrome were randomly assigned to a low or high dose of plant- (2.2 or 6.6 g/d α-linolenic acid) or marine- (1.2 or 3.6 g/d EPA and DHA) derived (n-3) FA or placebo for 8 wk, using a parallel arm design (n = 20/arm). Fasting blood samples collected at 0, 4, and 8 wk were analyzed for concentrations of monocyte chemotactic protein-1 (MCP-1), IL-6, and soluble intercellular adhesion molecule-1 (sICAM-1) and for cardiovascular risk factors. Baseline concentrations across all 5 groups combined were (mean ± SD) 103 ± 32 ng/L for MCP-1, 1.06 ± 0.56 ng/L for IL-6, and 0.197 ± 0.041 ng/L for sICAM-1. There were no significant differences in 8-wk changes in plasma inflammatory marker concentrations among the 5 groups. Plasma TG and blood pressure decreased significantly more and the LDL cholesterol concentration increased more in the high-dose fish oil group compared to the 8-wk changes in some of the other 4 groups (P ≤ 0.04). In conclusion, no beneficial effects were detected for any of the 3 inflammatory markers investigated in response to (n-3) FA in adults with metabolic syndrome regardless of dose or source.
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Affiliation(s)
- Antonella Dewell
- Stanford Prevention Research Center and Department of Medicine, and
| | | | - William S. Harris
- Cardiovascular Health Research Center Sanford Research/University of South Dakota, Sioux Falls, SD
| | - Philip Tsao
- Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA; and
| | - Christopher D. Gardner
- Stanford Prevention Research Center and Department of Medicine, and,To whom correspondence should be addressed. E-mail:
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Green CJ, Pedersen M, Pedersen BK, Scheele C. Elevated NF-κB activation is conserved in human myocytes cultured from obese type 2 diabetic patients and attenuated by AMP-activated protein kinase. Diabetes 2011; 60:2810-9. [PMID: 21911750 PMCID: PMC3198079 DOI: 10.2337/db11-0263] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To examine whether the inflammatory phenotype found in obese and diabetic individuals is preserved in isolated, cultured myocytes and to assess the effectiveness of pharmacological AMP-activated protein kinase (AMPK) activation upon the attenuation of inflammation in these myocytes. RESEARCH DESIGN AND METHODS Muscle precursor cells were isolated from four age-matched subject groups: 1) nonobese, normal glucose tolerant; 2) obese, normal glucose tolerant; 3) obese, impaired glucose tolerant; and 4) obese, type 2 diabetes (T2D). The level of inflammation (nuclear factor-κB [NF-κB] signaling) and effect of pharmacological AMPK activation was assessed by Western blots, enzyme-linked immunosorbent assay, and radioactive assays (n = 5 for each subject group). RESULTS NF-κB-p65 DNA binding activity was significantly elevated in myocytes from obese T2D patients compared with nonobese control subjects. This correlated to a significant increase in tumor necrosis factor-α concentration in cell culture media. In addition, insulin-stimulated glucose uptake was completely suppressed in myocytes from obese impaired glucose tolerant and T2D subjects. It is interesting that activation of AMPK by A769662 attenuated NF-κB-p65 DNA binding activity in obese T2D cells to levels measured in nonobese myocytes; however, this had no effect on insulin sensitivity of the cells. CONCLUSIONS This work provides solid evidence that differentiated human muscle precursor cells maintain in vivo phenotypes of inflammation and insulin resistance and that obesity alone may not be sufficient to establish inflammation in these cells. It is important that we demonstrate an anti-inflammatory role for AMPK in these human cells. Despite attenuation of NF-κB activity by AMPK, insulin resistance in obese T2D cells remained, suggesting factors in addition to inflammation may contribute to the insulin resistance phenotype in muscle cells.
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Affiliation(s)
- Charlotte J Green
- Centre of Inflammation and Metabolism, Department of Infectious Diseases, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
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Antillon D, Towfighi A. No Time to ‘Weight’: The Link between Obesity and Stroke in Women. WOMENS HEALTH 2011; 7:453-63. [DOI: 10.2217/whe.11.36] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The obesity epidemic in the USA threatens the gains that have been made in the prevention and treatment of stroke. Both obesity and stroke disproportionately affect women more than men. Understanding the effect of obesity on stroke risk in women may be a useful stepping stone to reducing the burden of stroke in this vulnerable population. This article reviews the association between stroke and general obesity, abdominal obesity and metabolic syndrome in women. All three factors have been shown to independently increase stroke risk in women.
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Affiliation(s)
| | - Amytis Towfighi
- Department of Neurology, University of Southern California, CA, USA
- Department of Neurology, Rancho Los Amigos National Rehabilitation Center, 7601 E. Imperial Highway, HB145, Downey, CA 90242, USA
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Inflammation in Relation to Cardiovascular Disease Risk: Comparison of Black and White Women in the United States, United Kingdom, and South Africa. CURRENT CARDIOVASCULAR RISK REPORTS 2011. [DOI: 10.1007/s12170-011-0168-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Klimcakova E, Roussel B, Kovacova Z, Kovacikova M, Siklova-Vitkova M, Combes M, Hejnova J, Decaunes P, Maoret JJ, Vedral T, Viguerie N, Bourlier V, Bouloumié A, Stich V, Langin D. Macrophage gene expression is related to obesity and the metabolic syndrome in human subcutaneous fat as well as in visceral fat. Diabetologia 2011; 54:876-87. [PMID: 21267541 DOI: 10.1007/s00125-010-2014-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2010] [Accepted: 11/25/2010] [Indexed: 12/28/2022]
Abstract
AIMS/HYPOTHESIS Our goal was to identify a set of human adipose tissue macrophage (ATM)-specific markers and investigate whether their gene expression in subcutaneous adipose tissue (SAT) as well as in visceral adipose tissue (VAT) is related to obesity and to the occurrence of the metabolic syndrome. METHODS ATM-specific markers were identified by DNA microarray analysis of adipose tissue cell types isolated from SAT of lean and obese individuals. We then analysed gene expression of these markers by reverse transcription quantitative PCR in paired samples of SAT and VAT from 53 women stratified into four groups (lean, overweight, obese and obese with the metabolic syndrome). Anthropometric measurements, euglycaemic-hyperinsulinaemic clamp, blood analysis and computed tomography scans were performed. RESULTS A panel of 24 genes was selected as ATM-specific markers based on overexpression in ATM compared with other adipose tissue cell types. In SAT and VAT, gene expression of ATM markers was lowest in lean and highest in the metabolic syndrome group. mRNA levels in the two fat depots were negatively correlated with glucose disposal rate and positively associated with indices of adiposity and the metabolic syndrome. CONCLUSIONS/INTERPRETATION In humans, expression of ATM-specific genes increases with the degree of adiposity and correlates with markers of insulin resistance and the metabolic syndrome to a similar degree in SAT and in VAT.
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Affiliation(s)
- E Klimcakova
- Franco-Czech Laboratory for Clinical Research on Obesity, Department of Sports Medicine, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic.
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Evans J, Goedecke JH, Söderström I, Burén J, Alvehus M, Blomquist C, Jonsson F, Hayes PM, Adams K, Dave JA, Levitt NS, Lambert EV, Olsson T. Depot- and ethnic-specific differences in the relationship between adipose tissue inflammation and insulin sensitivity. Clin Endocrinol (Oxf) 2011; 74:51-9. [PMID: 20874774 DOI: 10.1111/j.1365-2265.2010.03883.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE It is unclear whether there are differences in inflammatory gene expression between abdominal and gluteal subcutaneous adipose tissue (SAT), and between black and white women. We therefore tested the hypotheses that SAT inflammatory gene expression is greater in the abdominal compared to the gluteal depot, and SAT inflammatory gene expression is associated with differential insulin sensitivity (S(I) ) in black and white women. DESIGN AND METHODS S(I) (frequently sampled intravenous glucose tolerance test) and abdominal SAT and gluteal SAT gene expression levels of 13 inflammatory genes were measured in normal-weight (BMI 18-25 kg/m²) and obese (BMI >30 kg/m²) black (n = 30) and white (n = 26) South African women. RESULTS Black women had higher abdominal and gluteal SAT expression of CCL2, CD68, TNF-α and CSF-1 compared to white women (P < 0·01). Multivariate analysis showed that inflammatory gene expression in the white women explained 56·8% of the variance in S(I) (P < 0·005), compared to 20·9% in black women (P = 0·30). Gluteal SAT had lower expression of adiponectin, but higher expression of inflammatory cytokines, macrophage markers and leptin than abdominal SAT depots (P < 0·05). CONCLUSIONS Black South African women had higher inflammatory gene expression levels than white women; however, the relationship between AT inflammation and S(I) was stronger in white compared to black women. Further research is required to explore other factors affecting S(I) in black populations. Contrary to our original hypothesis, gluteal SAT had a greater inflammatory gene expression profile than abdominal SAT depots. The protective nature of gluteo-femoral fat therefore requires further investigation.
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Affiliation(s)
- Juliet Evans
- Department of Human Biology, the University of Cape Town, South African
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Liu A, Sonmez A, Yee G, Bazuine M, Arroyo M, Sherman A, McLaughlin T, Reaven G, Cushman S, Tsao P. Differential adipogenic and inflammatory properties of small adipocytes in Zucker Obese and Lean rats. Diab Vasc Dis Res 2010; 7:311-8. [PMID: 20961992 PMCID: PMC3462589 DOI: 10.1177/1479164110386126] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
We recently reported that a preponderance of small adipose cells, decreased expression of cell differentiation markers, and enhanced inflammatory activity in human subcutaneous whole adipose tissue were associated with insulin resistance. To test the hypothesis that small adipocytes exhibited these differential properties, we characterised small adipocytes from epididymal adipose tissue of Zucker Obese (ZO) and Lean (ZL) rats. Rat epididymal fat pads were removed and adipocytes isolated by collagenase digestion. Small adipocytes were separated by sequential filtration through nylon meshes. Adipocytes were fixed in osmium tetroxide for cell size distribution analysis via Beckman Coulter Multisizer. Quantitative real-time PCR for cell differentiation and inflammatory genes was performed. Small adipocytes represented a markedly greater percentage of the total adipocyte population in ZO than ZL rats (58±4% vs. 12±3%, p<0.001). In ZO rats, small as compared with total adipocytes had 4-fold decreased adiponectin, and 4-fold increased visfatin and IL-6 levels. Comparison of small adipocytes in ZO versus ZL rats revealed 3-fold decreased adiponectin and PPARγ levels, and 2.5-fold increased IL-6. In conclusion, ZO rat adipose tissue harbours a large proportion of small adipocytes that manifest impaired cell differentiation and pro-inflammatory activity, two mechanisms by which small adipocytes may contribute to insulin resistance.
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Affiliation(s)
- Alice Liu
- Division of Endocrinology, Department of Medicine, Stanford University Medical Center, CA 94305, USA.
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Adipose tissue inflammation and insulin resistance: all obese humans are not created equal. Biochem J 2010; 430:e1-4. [PMID: 20704568 DOI: 10.1042/bj20101062] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In recent years, it has become widely accepted that obesity is characterized by a chronic low-grade inflammation of adipose tissue that predisposes affected individuals to insulin resistance, Type 2 diabetes and other disorders associated with the metabolic syndrome. On the other hand, a subset of obese individuals appears to be protected against insulin resistance and the disorders to which it predisposes. The comparison between such insulin-sensitive and insulin-resistant obese individuals offers a unique opportunity to identify key factors that either contribute to or prevent the development of insulin resistance in humans, without the confounding effect of a major difference in fat mass. In the previous issue of the Biochemical Journal, Barbarroja et al. reported that insulin-sensitive obese individuals show less inflammation in their visceral adipose tissue than a group of insulin-resistant subjects matched for BMI (body mass index). This finding reinforces the concept that inflammation in adipose tissue may be a cause of insulin resistance in most obese individuals, although it does not prove it. Further studies will be required for this purpose, as well as to identify the pathogenetic factors that determine whether or not adipose tissue of an obese individual becomes inflamed.
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Wentworth JM, Naselli G, Brown WA, Doyle L, Phipson B, Smyth GK, Wabitsch M, O'Brien PE, Harrison LC. Pro-inflammatory CD11c+CD206+ adipose tissue macrophages are associated with insulin resistance in human obesity. Diabetes 2010; 59:1648-56. [PMID: 20357360 PMCID: PMC2889764 DOI: 10.2337/db09-0287] [Citation(s) in RCA: 450] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Accepted: 03/15/2010] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Insulin resistance and other features of the metabolic syndrome have been causally linked to adipose tissue macrophages (ATMs) in mice with diet-induced obesity. We aimed to characterize macrophage phenotype and function in human subcutaneous and omental adipose tissue in relation to insulin resistance in obesity. RESEARCH DESIGN AND METHODS Adipose tissue was obtained from lean and obese women undergoing bariatric surgery. Metabolic markers were measured in fasting serum and ATMs characterized by immunohistology, flow cytometry, and tissue culture studies. RESULTS ATMs comprised CD11c(+)CD206(+) cells in "crown" aggregates and solitary CD11c(-)CD206(+) cells at adipocyte junctions. In obese women, CD11c(+) ATM density was greater in subcutaneous than omental adipose tissue and correlated with markers of insulin resistance. CD11c(+) ATMs were distinguished by high expression of integrins and antigen presentation molecules; interleukin (IL)-1beta, -6, -8, and -10; tumor necrosis factor-alpha; and CC chemokine ligand-3, indicative of an activated, proinflammatory state. In addition, CD11c(+) ATMs were enriched for mitochondria and for RNA transcripts encoding mitochondrial, proteasomal, and lysosomal proteins, fatty acid metabolism enzymes, and T-cell chemoattractants, whereas CD11c(-) ATMs were enriched for transcripts involved in tissue maintenance and repair. Tissue culture medium conditioned by CD11c(+) ATMs, but not CD11c(-) ATMs or other stromovascular cells, impaired insulin-stimulated glucose uptake by human adipocytes. CONCLUSIONS These findings identify proinflammatory CD11c(+) ATMs as markers of insulin resistance in human obesity. In addition, the machinery of CD11c(+) ATMs indicates they metabolize lipid and may initiate adaptive immune responses.
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Affiliation(s)
- John M. Wentworth
- Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute of Medical Research, Victoria, Australia
- Burnet Clinical Research Unit, Royal Melbourne Hospital, Victoria, Australia
- Centre for Obesity Research and Education, Monash University, Commercial Road, Victoria, Australia
| | - Gaetano Naselli
- Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute of Medical Research, Victoria, Australia
| | - Wendy A. Brown
- Centre for Obesity Research and Education, Monash University, Commercial Road, Victoria, Australia
| | - Lisa Doyle
- Centre for Obesity Research and Education, Monash University, Commercial Road, Victoria, Australia
| | - Belinda Phipson
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Victoria, Australia
| | - Gordon K. Smyth
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Victoria, Australia
| | - Martin Wabitsch
- Department of Pediatrics and Adolescent Medicine, University of Ulm, Ulm, Germany
| | - Paul E. O'Brien
- Centre for Obesity Research and Education, Monash University, Commercial Road, Victoria, Australia
| | - Leonard C. Harrison
- Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute of Medical Research, Victoria, Australia
- Burnet Clinical Research Unit, Royal Melbourne Hospital, Victoria, Australia
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Lam KD, Bacchetti P, Abbasi F, Ayala CE, Loeb SM, Shah V, Wen MJ, Reaven GM, Maher JJ, Khalili M. Comparison of surrogate and direct measurement of insulin resistance in chronic hepatitis C virus infection: impact of obesity and ethnicity. Hepatology 2010; 52:38-46. [PMID: 20578127 PMCID: PMC4391817 DOI: 10.1002/hep.23670] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
UNLABELLED Studies using surrogate estimates show high prevalence of insulin resistance in hepatitis C infection. This study prospectively evaluated the correlation between surrogate and directly measured estimates of insulin resistance and the impact of obesity and ethnicity on this relationship. Eighty-six nondiabetic, noncirrhotic patients with hepatitis C virus (age = 48 +/- 7 years, 74% male, 44% white, 22% African American, 26% Latino, 70% genotype 1) were categorized into normal-weight (body mass index [BMI] < 25, n = 30), overweight (BMI = 25-29.9, n = 38), and obese (BMI > or = 30, n = 18). Insulin-mediated glucose uptake was measured by steady-state plasma glucose (SSPG) concentration during a 240-minute insulin suppression test. Surrogate estimates included: fasting glucose and insulin, glucose/insulin, homeostasis model assessment (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), insulin (I-AUC) and glucose (G-AUC) area under the curve during oral glucose tolerance test, and the Belfiore and Stumvoll indexes. All surrogate estimates correlated with SSPG, but the magnitude of correlation varied (r = 0.30-0.64). The correlation coefficients were highest in the obese. I-AUC had the highest correlation among all ethnic and weight groups (r = 0.57-0.77). HOMA-IR accounted for only 15% of variability in SSPG in the normal weight group. The common HOMA-IR cutoff of < or =3 to define insulin resistance had high misclassification rates especially in the overweight group independent of ethnicity. HOMA-IR > 4 had the lowest misclassification rate (75% sensitivity, 88% specificity). Repeat HOMA-IR measurements had higher within-person variation in the obese (standard deviation = 0.77 higher than normal-weight, 95% confidence interval = 0.25-1.30, P = 0.005). CONCLUSION Because of limitations of surrogate estimates, caution should be used in interpreting data evaluating insulin resistance especially in nonobese, nondiabetic patients with HCV.
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Affiliation(s)
- Khoa D. Lam
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA
| | - Peter Bacchetti
- Department of Epidemiology and Biostatistics, University of California San Francisco (UCSF), San Francisco, CA
| | - Fahim Abbasi
- Department of Medicine, Stanford University Medical Center, Palo Alto, CA
| | - Claudia E. Ayala
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA
| | - Samuel M. Loeb
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA
| | - Vidhi Shah
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA
| | - Michael J. Wen
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA
| | - Gerald M. Reaven
- Department of Medicine, Stanford University Medical Center, Palo Alto, CA
| | - Jacquelyn J. Maher
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA
| | - Mandana Khalili
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA
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Manickam E, Sinclair AJ, Cameron-Smith D. Suppressive actions of eicosapentaenoic acid on lipid droplet formation in 3T3-L1 adipocytes. Lipids Health Dis 2010; 9:57. [PMID: 20525346 PMCID: PMC2895668 DOI: 10.1186/1476-511x-9-57] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 06/04/2010] [Indexed: 11/25/2022] Open
Abstract
Background Lipid droplet (LD) formation and size regulation reflects both lipid influx and efflux, and is central in the regulation of adipocyte metabolism, including adipokine secretion. The length and degree of dietary fatty acid (FA) unsaturation is implicated in LD formation and regulation in adipocytes. The aims of this study were to establish the impact of eicosapentaenoic acid (EPA; C20:5n-3) in comparison to SFA (STA; stearic acid, C18:0) and MUFA (OLA; oleic acid, C18:1n-9) on 3T3-L1 adipocyte LD formation, regulation of genes central to LD function and adipokine responsiveness. Cells were supplemented with 100 μM FA during 7-day differentiation. Results EPA markedly reduced LD size and total lipid accumulation, suppressing PPARγ, Cidea and D9D/SCD1 genes, distinct from other treatments. These changes were independent of alterations of lipolytic genes, as both EPA and STA similarly elevated LPL and HSL gene expressions. In response to acute lipopolysaccharide exposure, EPA-differentiated adipocytes had distinct improvement in inflammatory response shown by reduction in monocyte chemoattractant protein-1 and interleukin-6 and elevation in adiponectin and leptin gene expressions. Conclusions This study demonstrates that EPA differentially modulates adipogenesis and lipid accumulation to suppress LD formation and size. This may be due to suppressed gene expression of key proteins closely associated with LD function. Further analysis is required to determine if EPA exerts a similar influence on LD formation and regulation in-vivo.
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Affiliation(s)
- Elizabeth Manickam
- Molecular Nutrition Unit, School of Exercise and Nutrition Sciences, Faculty of Health, Medicine, Nursing and Behavioural Sciences, Deakin University, Melbourne, Victoria, Australia
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Daigle BJ, Deng A, McLaughlin T, Cushman SW, Cam MC, Reaven G, Tsao PS, Altman RB. Using pre-existing microarray datasets to increase experimental power: application to insulin resistance. PLoS Comput Biol 2010; 6:e1000718. [PMID: 20361040 PMCID: PMC2845644 DOI: 10.1371/journal.pcbi.1000718] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 02/22/2010] [Indexed: 11/18/2022] Open
Abstract
Although they have become a widely used experimental technique for identifying differentially expressed (DE) genes, DNA microarrays are notorious for generating noisy data. A common strategy for mitigating the effects of noise is to perform many experimental replicates. This approach is often costly and sometimes impossible given limited resources; thus, analytical methods are needed which increase accuracy at no additional cost. One inexpensive source of microarray replicates comes from prior work: to date, data from hundreds of thousands of microarray experiments are in the public domain. Although these data assay a wide range of conditions, they cannot be used directly to inform any particular experiment and are thus ignored by most DE gene methods. We present the SVD Augmented Gene expression Analysis Tool (SAGAT), a mathematically principled, data-driven approach for identifying DE genes. SAGAT increases the power of a microarray experiment by using observed coexpression relationships from publicly available microarray datasets to reduce uncertainty in individual genes' expression measurements. We tested the method on three well-replicated human microarray datasets and demonstrate that use of SAGAT increased effective sample sizes by as many as 2.72 arrays. We applied SAGAT to unpublished data from a microarray study investigating transcriptional responses to insulin resistance, resulting in a 50% increase in the number of significant genes detected. We evaluated 11 (58%) of these genes experimentally using qPCR, confirming the directions of expression change for all 11 and statistical significance for three. Use of SAGAT revealed coherent biological changes in three pathways: inflammation, differentiation, and fatty acid synthesis, furthering our molecular understanding of a type 2 diabetes risk factor. We envision SAGAT as a means to maximize the potential for biological discovery from subtle transcriptional responses, and we provide it as a freely available software package that is immediately applicable to any human microarray study.
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Affiliation(s)
- Bernie J. Daigle
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Alicia Deng
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Tracey McLaughlin
- Division of Endocrinology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Samuel W. Cushman
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Margaret C. Cam
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Gerald Reaven
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Philip S. Tsao
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Russ B. Altman
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Bioengineering, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
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McLaughlin T, Deng A, Yee G, Lamendola C, Reaven G, Tsao PS, Cushman SW, Sherman A. Inflammation in subcutaneous adipose tissue: relationship to adipose cell size. Diabetologia 2010; 53:369-77. [PMID: 19816674 PMCID: PMC6290757 DOI: 10.1007/s00125-009-1496-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 07/16/2009] [Indexed: 11/28/2022]
Abstract
AIMS/HYPOTHESIS Inflammation is associated with increased body mass and purportedly with increased size of adipose cells. We sought to determine whether increased size of adipose cells is associated with localised inflammation in weight-stable, moderately obese humans. METHODS We recruited 49 healthy, moderately obese individuals for quantification of insulin resistance (modified insulin suppression test) and subcutaneous abdominal adipose tissue biopsy. Cell size distribution was analysed with a multisizer device and inflammatory gene expression with real-time PCR. Correlations between inflammatory gene expression and cell size variables, with adjustment for sex and insulin resistance, were calculated. RESULTS Adipose cells were bimodally distributed, with 47% in a 'large' cell population and the remainder in a 'small' cell population. The median diameter of the large adipose cells was not associated with expression of inflammatory genes. Rather, the fraction of small adipose cells was consistently associated with inflammatory gene expression, independently of sex, insulin resistance and BMI. This association was more pronounced in insulin-resistant than insulin-sensitive individuals. Insulin resistance also independently predicted expression of inflammatory genes. CONCLUSIONS/INTERPRETATION This study demonstrates that among moderately obese, weight-stable individuals an increased proportion of small adipose cells is associated with inflammation in subcutaneous adipose tissue, whereas size of mature adipose cells is not. The observed association between small adipose cells and inflammation may reflect impaired adipogenesis and/or terminal differentiation. However, it is unclear whether this is a cause or consequence of inflammation. This question and whether small vs large adipose cells contribute differently to inflammation in adipose tissue are topics for future research. TRIAL REGISTRATION ClinicalTrials.gov NCT00285844.
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Affiliation(s)
- T McLaughlin
- Division of Endocrinology, Stanford University School of Medicine, 300 Pasteur Drive, Rm S025, Stanford, CA 94305-5103, USA.
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Liu A, McLaughlin T, Liu T, Sherman A, Yee G, Abbasi F, Lamendola C, Morton J, Cushman SW, Reaven GM, Tsao PS. Differential intra-abdominal adipose tissue profiling in obese, insulin-resistant women. Obes Surg 2009; 19:1564-73. [PMID: 19711137 PMCID: PMC3181138 DOI: 10.1007/s11695-009-9949-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Accepted: 08/11/2009] [Indexed: 02/08/2023]
Abstract
BACKGROUND We recently identified differences in abdominal subcutaneous adipose tissue (SAT) from insulin-resistant (IR) as compared to obesity-matched insulin sensitive individuals, including accumulation of small adipose cells, decreased expression of cell differentiation markers, and increased inflammatory activity. This study was initiated to see if these changes in SAT of IR individuals were present in omental visceral adipose tissue (VAT); in this instance, individuals were chosen to be IR but varied in degree of adiposity. We compared cell size distribution and genetic markers in SAT and VAT of IR individuals undergoing bariatric surgery. METHODS Eleven obese/morbidly obese women were IR by the insulin suppression test. Adipose tissue surgical samples were fixed in osmium tetroxide for cell size analysis via Beckman Coulter Multisizer. Quantitative real-time polymerase chain reaction for genes related to adipocyte differentiation and inflammation was performed. RESULTS While proportion of small cells and expression of adipocyte differentiation genes did not differ between depots, inflammatory genes were upregulated in VAT. Diameter of SAT large cells correlated highly with increasing proportion of small cells in both SAT and VAT (r = 0.85, p = 0.001; r = 0.72, p = 0.01, respectively). No associations were observed between VAT large cells and cell size variables in either depot. The effect of body mass index (BMI) on any variables in both depots was negligible. CONCLUSIONS The major differential property of VAT of IR women is increased inflammatory activity, independent of BMI. The association of SAT adipocyte hypertrophy with hyperplasia in both depots suggests a primary role SAT may have in regulating regional fat storage.
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Affiliation(s)
- Alice Liu
- Division of Endocrinology, Department of Medicine, Stanford University Medical Center, 300 Pasteur Drive Rm S-025, Stanford, CA 94305, USA.
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