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Tian IY, Wong MC, Nguyen WM, Kennedy S, McCarthy C, Kelly NN, Liu YE, Garber AK, Heymsfield SB, Curless B, Shepherd JA. Automated body composition estimation from device-agnostic 3D optical scans in pediatric populations. Clin Nutr 2023; 42:1619-1630. [PMID: 37481870 PMCID: PMC10528749 DOI: 10.1016/j.clnu.2023.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/19/2023] [Accepted: 07/12/2023] [Indexed: 07/25/2023]
Abstract
BACKGROUND Excess adiposity in children is strongly correlated with obesity-related metabolic disease in adulthood, including diabetes, cardiovascular disease, and 13 types of cancer. Despite the many long-term health risks of childhood obesity, body mass index (BMI) Z-score is typically the only adiposity marker used in pediatric studies and clinical applications. The effects of regional adiposity are not captured in a single scalar measurement, and their effects on short- and long-term metabolic health are largely unknown. However, clinicians and researchers rarely deploy gold-standard methods for measuring compartmental fat such as magnetic resonance imaging (MRI) and dual X-ray absorptiometry (DXA) on children and adolescents due to cost or radiation concerns. Three-dimensional optical (3DO) scans are relatively inexpensive to obtain and use non-invasive and radiation-free imaging techniques to capture the external surface geometry of a patient's body. This 3D shape contains cues about the body composition that can be learned from a structured correlation between 3D body shape parameters and reference DXA scans obtained on a sample population. STUDY AIM This study seeks to introduce a radiation-free, automated 3D optical imaging solution for monitoring body shape and composition in children aged 5-17. METHODS We introduce an automated, linear learning method to predict total and regional body composition of children aged 5-17 from 3DO scans. We collected 145 male and 206 female 3DO scans on children between the ages of 5 and 17 with three scanners from independent manufacturers. We used an automated shape templating method first introduced on an adult population to fit a topologically consistent 60,000 vertex (60 k) mesh to 3DO scans of arbitrary scanning source and mesh topology. We constructed a parameterized body shape space using principal component analysis (PCA) and estimated a regression matrix between the shape parameters and their associated DXA measurements. We automatically fit scans of 30 male and 38 female participants from a held-out test set and predicted 12 body composition measurements. RESULTS The coefficient of determination (R2) between 3DO predicted body composition and DXA measurements was at least 0.85 for all measurements with the exception of visceral fat on 3D scan predictions. Precision error was 1-4 times larger than that of DXA. No predicted variable was significantly different from DXA measurement except for male trunk lean mass. CONCLUSION Optical imaging can quickly, safely, and inexpensively estimate regional body composition in children aged 5-17. Frequent repeat measurements can be taken to chart changes in body adiposity over time without risk of radiation overexposure.
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Affiliation(s)
- Isaac Y Tian
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, 98195, USA.
| | - Michael C Wong
- University of Hawaii Cancer Center, University of Hawaii - Manoa, Honolulu, HI, 96813, USA
| | - William M Nguyen
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Samantha Kennedy
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, 70808, USA
| | - Cassidy McCarthy
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, 70808, USA
| | - Nisa N Kelly
- University of Hawaii Cancer Center, University of Hawaii - Manoa, Honolulu, HI, 96813, USA
| | - Yong E Liu
- University of Hawaii Cancer Center, University of Hawaii - Manoa, Honolulu, HI, 96813, USA
| | - Andrea K Garber
- UCSF School of Medicine, University of California - San Francisco, San Francisco, CA, 94118, USA
| | - Steven B Heymsfield
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, 70808, USA
| | - Brian Curless
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, 98195, USA
| | - John A Shepherd
- University of Hawaii Cancer Center, University of Hawaii - Manoa, Honolulu, HI, 96813, USA
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Zhao X, An X, Yang C, Sun W, Ji H, Lian F. The crucial role and mechanism of insulin resistance in metabolic disease. Front Endocrinol (Lausanne) 2023; 14:1149239. [PMID: 37056675 PMCID: PMC10086443 DOI: 10.3389/fendo.2023.1149239] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 03/07/2023] [Indexed: 03/30/2023] Open
Abstract
Insulin resistance (IR) plays a crucial role in the development and progression of metabolism-related diseases such as diabetes, hypertension, tumors, and nonalcoholic fatty liver disease, and provides the basis for a common understanding of these chronic diseases. In this study, we provide a systematic review of the causes, mechanisms, and treatments of IR. The pathogenesis of IR depends on genetics, obesity, age, disease, and drug effects. Mechanistically, any factor leading to abnormalities in the insulin signaling pathway leads to the development of IR in the host, including insulin receptor abnormalities, disturbances in the internal environment (regarding inflammation, hypoxia, lipotoxicity, and immunity), metabolic function of the liver and organelles, and other abnormalities. The available therapeutic strategies for IR are mainly exercise and dietary habit improvement, and chemotherapy based on biguanides and glucagon-like peptide-1, and traditional Chinese medicine treatments (e.g., herbs and acupuncture) can also be helpful. Based on the current understanding of IR mechanisms, there are still some vacancies to follow up and consider, and there is also a need to define more precise biomarkers for different chronic diseases and lifestyle interventions, and to explore natural or synthetic drugs targeting IR treatment. This could enable the treatment of patients with multiple combined metabolic diseases, with the aim of treating the disease holistically to reduce healthcare expenditures and to improve the quality of life of patients to some extent.
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Affiliation(s)
| | | | | | | | - Hangyu Ji
- *Correspondence: Fengmei Lian, ; Hangyu Ji,
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Accili D, Du W, Kitamoto T, Kuo T, McKimpson W, Miyachi Y, Mukhanova M, Son J, Wang L, Watanabe H. Reflections on the state of diabetes research and prospects for treatment. Diabetol Int 2023; 14:21-31. [PMID: 36636157 PMCID: PMC9829952 DOI: 10.1007/s13340-022-00600-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/02/2022] [Indexed: 01/16/2023]
Abstract
Research on the etiology and treatment of diabetes has made substantial progress. As a result, several new classes of anti-diabetic drugs have been introduced in clinical practice. Nonetheless, the number of patients achieving glycemic control targets has not increased for the past 20 years. Two areas of unmet medical need are the restoration of insulin sensitivity and the reversal of pancreatic beta cell failure. In this review, we integrate research advances in transcriptional regulation of insulin action and pathophysiology of beta cell dedifferentiation with their potential impact on prospects of a durable "cure" for patients suffering from type 2 diabetes.
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Affiliation(s)
- Domenico Accili
- Department of Medicine and Berrie Diabetes Center, Vagelos College of Physicians and Surgeons of Columbia University, New York, NY 10032 USA
| | - Wen Du
- Department of Medicine and Berrie Diabetes Center, Vagelos College of Physicians and Surgeons of Columbia University, New York, NY 10032 USA
| | - Takumi Kitamoto
- Department of Endocrinology, Hematology and Gerontology, Chiba University Graduate School of Medicine, Chiba, Chiba 260-8670 Japan
| | - Taiyi Kuo
- Department of Neurobiology, Physiology, and Behavior, University of California at Davis, Davis, CA 95616 USA
| | - Wendy McKimpson
- Department of Medicine and Berrie Diabetes Center, Vagelos College of Physicians and Surgeons of Columbia University, New York, NY 10032 USA
| | - Yasutaka Miyachi
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka Japan
| | - Maria Mukhanova
- Department of Medicine and Berrie Diabetes Center, Vagelos College of Physicians and Surgeons of Columbia University, New York, NY 10032 USA
| | - Jinsook Son
- Department of Medicine and Berrie Diabetes Center, Vagelos College of Physicians and Surgeons of Columbia University, New York, NY 10032 USA
| | - Liheng Wang
- Department of Medicine and Berrie Diabetes Center, Vagelos College of Physicians and Surgeons of Columbia University, New York, NY 10032 USA
| | - Hitoshi Watanabe
- Department of Medicine and Berrie Diabetes Center, Vagelos College of Physicians and Surgeons of Columbia University, New York, NY 10032 USA
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Adipocyte Phenotype Flexibility and Lipid Dysregulation. Cells 2022; 11:cells11050882. [PMID: 35269504 PMCID: PMC8909878 DOI: 10.3390/cells11050882] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/22/2022] [Accepted: 03/01/2022] [Indexed: 12/04/2022] Open
Abstract
The prevalence of obesity and associated cardiometabolic diseases continues to rise, despite efforts to improve global health. The adipose tissue is now regarded as an endocrine organ since its multitude of secretions, lipids chief among them, regulate systemic functions. The loss of normal adipose tissue phenotypic flexibility, especially related to lipid homeostasis, appears to trigger cardiometabolic pathogenesis. The goal of this manuscript is to review lipid balance maintenance by the lean adipose tissue’s propensity for phenotype switching, obese adipose tissue’s narrower range of phenotype flexibility, and what initial factors account for the waning lipid regulatory capacity. Metabolic, hypoxic, and inflammatory factors contribute to the adipose tissue phenotype being made rigid. A better grasp of normal adipose tissue function provides the necessary context for recognizing the extent of obese adipose tissue dysfunction and gaining insight into how pathogenesis evolves.
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Role of Distinct Fat Depots in Metabolic Regulation and Pathological Implications. Rev Physiol Biochem Pharmacol 2022; 186:135-176. [PMID: 35915363 DOI: 10.1007/112_2022_73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
People suffering from obesity and associated metabolic disorders including diabetes are increasing exponentially around the world. Adipose tissue (AT) distribution and alteration in their biochemical properties play a major role in the pathogenesis of these diseases. Emerging evidence suggests that AT heterogeneity and depot-specific physiological changes are vital in the development of insulin resistance in peripheral tissues like muscle and liver. Classically, AT depots are classified into white adipose tissue (WAT) and brown adipose tissue (BAT); WAT is the site of fatty acid storage, while BAT is a dedicated organ of metabolic heat production. The discovery of beige adipocyte clusters in WAT depots indicates AT heterogeneity has a more central role than hither to ascribed. Therefore, we have discussed in detail the current state of understanding on cellular and molecular origin of different AT depots and their relevance toward physiological metabolic homeostasis. A major focus is to highlight the correlation between altered WAT distribution in the body and metabolic pathogenesis in animal models and humans. We have also underscored the disparity in the molecular (including signaling) changes in various WAT tissues during diabetic pathogenesis. Exercise-mediated beneficial alteration in WAT physiology/distribution that protects against metabolic disorders is evolving. Here we have discussed the depot-specific biochemical adjustments induced by different forms of exercise. A detailed understanding of the molecular details of inter-organ crosstalk via substrate utilization/storage and signaling through chemokines provide strategies to target selected WAT depots to pharmacologically mimic the benefits of exercise countering metabolic diseases including diabetes.
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Arya S, Gourley AJ, Penedo JC, Blindauer CA, Stewart AJ. Fatty acids may influence insulin dynamics through modulation of albumin-Zn 2+ interactions. Bioessays 2021; 43:e2100172. [PMID: 34725844 DOI: 10.1002/bies.202100172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 01/02/2023]
Abstract
Insulin is stored within the pancreas in an inactive Zn2+ -bound hexameric form prior to release. Similarly, clinical insulins contain Zn2+ and form multimeric complexes. Upon release from the pancreas or upon injection, insulin only becomes active once Zn2+ disengages from the complex. In plasma and other extracellular fluids, the majority of Zn2+ is bound to human serum albumin (HSA), which plays a vital role in controlling insulin pharmacodynamics by enabling removal of Zn2+ . The Zn2+ -binding properties of HSA are attenuated by non-esterified fatty acids (NEFAs) also transported by HSA. Elevated NEFA concentrations are associated with obesity and type 2 diabetes. Here we present the hypothesis that higher NEFA levels in obese and/or diabetic individuals may contribute to insulin resistance and affect therapeutic insulin dose-response profiles, through modulation of HSA/Zn2+ dynamics. We envisage this novel concept to have important implications for personalized treatments and management of diabetes-related conditions in the future.
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Affiliation(s)
- Swati Arya
- School of Medicine, University of St. Andrews, St. Andrews, Fife, UK
| | - Adam J Gourley
- School of Medicine, University of St. Andrews, St. Andrews, Fife, UK
| | - J Carlos Penedo
- Biomedical Sciences Research Complex, University of St. Andrews, St. Andrews, Fife, UK
| | | | - Alan J Stewart
- School of Medicine, University of St. Andrews, St. Andrews, Fife, UK
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Rezazadeh H, Sharifi MR, Soltani N. Insulin resistance and the role of gamma-aminobutyric acid. JOURNAL OF RESEARCH IN MEDICAL SCIENCES 2021; 26:39. [PMID: 34484371 PMCID: PMC8384006 DOI: 10.4103/jrms.jrms_374_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 12/09/2020] [Accepted: 02/02/2021] [Indexed: 12/17/2022]
Abstract
Insulin resistance (IR) is mentioned to be a disorder in insulin ability in insulin-target tissues. Skeletal muscle (SkM) and liver function are more affected by IR than other insulin target cells. SkM is the main site for the consumption of ingested glucose. An effective treatment for IR has two properties: An inhibition of β-cell death and a promotion of β-cell replication. Gamma-aminobutyric acid (GABA) can improve beta-cell mass and function. Multiple studies have shown that GABA decreases IR probably via increase in glucose transporter 4 (GLUT4) gene expression and prevention of gluconeogenesis pathway in the liver. This review focused on the general aspects of IR in skeletal muscle (SkM), liver; the cellular mechanism(s) lead to the development of IR in these organs, and the role of GABA to reduce insulin resistance.
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Affiliation(s)
- Hossein Rezazadeh
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
| | - Mohammad Reza Sharifi
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
| | - Nepton Soltani
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
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Abaj F, Saeedy SAG, Mirzaei K. Are caveolin-1 minor alleles more likely to be risk alleles in insulin resistance mechanisms in metabolic diseases? BMC Res Notes 2021; 14:185. [PMID: 34001235 PMCID: PMC8130340 DOI: 10.1186/s13104-021-05597-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 05/05/2021] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES Obesity and insulin resistance (IR) are interrelated in a range of ways. The IR-obesity relationship is not a cause-and-effect association. Molecular biology research has made tremendous strides in discovering contributors to find this association. Genes that control adipocyte function such as caveolin-1 (CAV1); probably interact in the pathogenesis of human IR in this context. The involvement of CAV1 in glucose/lipid homeostasis is revealed and could modify the signaling of the insulin receptor. We examined the association between CAV1 and insulin signaling in modifying dyslipidemia and fat composition in overweight and obese women with a prevalent variant in the CAV1 gene. RESULTS Minor allele carriers were slightly older and had higher BMI (p = 0.02), FMI (p = 0.006), and VLF (p = 0.01) values; and tended to have lower total cholesterol TC (p = 0.04), low-density lipoprotein cholesterol (LDL-C) (p = 0.001) and high-density lipoprotein cholesterol (HDL-C) (p = 0.003). HOMA-IR levels predicted fat mass index (FMI) 0.47 (0.08, 0.87), visceral fat level (VFL) 0.65 (0.23, 1.07), TC 6.82 (1.76, 11.88) and HDL-C - 1.663 (- 3.11, - 0.214) only between minor allele carriers in adjusted models. (β, CI). Our results cast a new light on the IR mechanism and future studies will elucidate the clinical relevance of CAV1-IR in patients with dyslipidemia and high fat composition.
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Affiliation(s)
- Faezeh Abaj
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), No. 44, Hojjat-dost Alley, Naderi St., Keshavarz Blvd, P.O. Box, 14155-6117, Tehran, Iran
| | | | - Khadijeh Mirzaei
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), No. 44, Hojjat-dost Alley, Naderi St., Keshavarz Blvd, P.O. Box, 14155-6117, Tehran, Iran.
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Abdul-Ghani MA, Jayyousi A, DeFronzo RA, Asaad N, Al-Suwaidi J. Insulin Resistance the Link between T2DM and CVD: Basic Mechanisms and Clinical Implications. Curr Vasc Pharmacol 2020; 17:153-163. [PMID: 29032755 DOI: 10.2174/1570161115666171010115119] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 09/05/2017] [Accepted: 09/27/2017] [Indexed: 01/04/2023]
Abstract
Insulin resistance (IR) is a cardinal feature of type 2 diabetes mellitus (T2DM). It also is associated with multiple metabolic abnormalities which are known cardiovascular disease (CVD) risk factors. Thus, IR not only contributes to the development of hyperglycemia in T2DM patients, but also to the elevated CVD risk. Improving insulin sensitivity is anticipated to both lower the plasma glucose concentration and decrease CVD risk in T2DM patients, independent of glucose control. We review the molecular mechanisms and metabolic consequences of IR in T2DM patients and discuss the importance of addressing IR in the management of T2DM.
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Affiliation(s)
- Muhammad A Abdul-Ghani
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, United States.,Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Amin Jayyousi
- Cardio-Metabolic Institute, Hamad Medical Corporation, Doha, Qatar
| | - Ralph A DeFronzo
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, United States
| | - Nidal Asaad
- Cardio-Metabolic Institute, Hamad Medical Corporation, Doha, Qatar
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Park S, Yoo HJ, Jee SH, Lee JH, Kim M. Weighting approaches for a genetic risk score and an oxidative stress score for predicting the incidence of obesity. Diabetes Metab Res Rev 2020; 36:e3230. [PMID: 31654550 DOI: 10.1002/dmrr.3230] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/09/2019] [Accepted: 10/06/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND We aimed to predict the incidence of obesity in a Korean population using a genetic risk score (GRS) constructed with obesity-related single nucleotide polymorphisms (SNPs) along with an oxidative stress score (OSS). METHODS A total of 9460 Korean subjects and 356 974 SNPs were included. The GRS was constructed using three significant obesity-related SNP loci, and the OSS was calculated with three reliable oxidative stress biomarkers. RESULTS The GRS showed a more significant association with increased obesity (OR = 2.879) than did individual SNPs after adjusting for age and sex. Three oxidative stress biomarkers, including malondialdehyde, oxidized low-density lipoprotein, and 8-epi-prostaglandin F2α , showed significantly high levels in the obese group. The OSS, which was the sum of each oxidative stress biomarker score, showed a markedly high association with the incidence of obesity, with an OR of 3.213. Based on the results of the regression tests and a receiver-operating characteristic (ROC) curve analysis, we found that HOMA-IR, high-sensitivity C-reactive protein (hs-CRP), the GRS, and the OSS were the most relevant factors for the increased risk of obesity and were significantly associated with the incidence of obesity. The area under the ROC curve was improved when the GRS was added to the model (from 74.2% to 75.1%). CONCLUSIONS We first identified that subjects with an obesity GRS and a high OSS might have a higher risk of obesity. Our findings and weighting approaches were effective in predicting the incidence of obesity; furthermore, the GRS is a relevant factor that significantly predicts the risk of obesity.
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Affiliation(s)
- Seonmin Park
- Department of Science for Aging, Graduate School of Yonsei University, Seoul, Korea
| | - Hye Jin Yoo
- Research Center for Silver Science, Institute of Symbiotic Life-TECH, Yonsei University, Seoul, Korea
- National Leading Research Laboratory of Clinical Nutrigenetics/Nutrigenomics, Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, Korea
| | - Sun Ha Jee
- Department of Epidemiology and Health Promotion, Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, Korea
| | - Jong Ho Lee
- Research Center for Silver Science, Institute of Symbiotic Life-TECH, Yonsei University, Seoul, Korea
- National Leading Research Laboratory of Clinical Nutrigenetics/Nutrigenomics, Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, Korea
| | - Minjoo Kim
- Research Center for Silver Science, Institute of Symbiotic Life-TECH, Yonsei University, Seoul, Korea
- National Leading Research Laboratory of Clinical Nutrigenetics/Nutrigenomics, Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, Korea
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Abstract
Obesity and type 2 diabetes are the most frequent metabolic disorders, but their causes remain largely unclear. Insulin resistance, the common underlying abnormality, results from imbalance between energy intake and expenditure favouring nutrient-storage pathways, which evolved to maximize energy utilization and preserve adequate substrate supply to the brain. Initially, dysfunction of white adipose tissue and circulating metabolites modulate tissue communication and insulin signalling. However, when the energy imbalance is chronic, mechanisms such as inflammatory pathways accelerate these abnormalities. Here we summarize recent studies providing insights into insulin resistance and increased hepatic gluconeogenesis associated with obesity and type 2 diabetes, focusing on data from humans and relevant animal models.
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Pérez-Pevida B, Escalada J, Miras AD, Frühbeck G. Mechanisms Underlying Type 2 Diabetes Remission After Metabolic Surgery. Front Endocrinol (Lausanne) 2019; 10:641. [PMID: 31608010 PMCID: PMC6761227 DOI: 10.3389/fendo.2019.00641] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 09/04/2019] [Indexed: 01/19/2023] Open
Abstract
Type 2 diabetes prevalence is increasing dramatically worldwide. Metabolic surgery is the most effective treatment for selected patients with diabetes and/or obesity. When compared to intensive medical therapy and lifestyle intervention, metabolic surgery has shown superiority in achieving glycemic improvement, reducing number of medications and cardiovascular risk factors, which translates in long-term benefits on cardiovascular morbidity and mortality. The mechanisms underlying diabetes improvement after metabolic surgery have not yet been clearly understood but englobe a complex interaction among improvements in beta cell function and insulin secretion, insulin sensitivity, intestinal gluconeogenesis, changes in glucose utilization, and absorption by the gut and changes in the secretory pattern and morphology of adipose tissue. These are achieved through different mediators which include an enhancement in gut hormones release, especially, glucagon-like peptide 1, changes in bile acids circulation, gut microbiome, and glucose transporters expression. Therefore, this review aims to provide a comprehensive appraisal of what is known so far to better understand the mechanisms through which metabolic surgery improves glycemic control facilitating future research in the field.
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Affiliation(s)
- Belén Pérez-Pevida
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, Hammersmith Campus, London, United Kingdom
- Department of Endocrinology and Nutrition, Clínica Universidad de Navarra, Pamplona, Spain
- *Correspondence: Belén Pérez-Pevida
| | - Javier Escalada
- Department of Endocrinology and Nutrition, Clínica Universidad de Navarra, Pamplona, Spain
- Biomedical Research Networking Center for Physiopathology of Obesity and Nutrition (CIBEROBN), ISCIII, Pamplona, Spain
- Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Alexander D. Miras
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, Hammersmith Campus, London, United Kingdom
| | - Gema Frühbeck
- Department of Endocrinology and Nutrition, Clínica Universidad de Navarra, Pamplona, Spain
- Biomedical Research Networking Center for Physiopathology of Obesity and Nutrition (CIBEROBN), ISCIII, Pamplona, Spain
- Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
- Gema Frühbeck
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Petersen MC, Shulman GI. Mechanisms of Insulin Action and Insulin Resistance. Physiol Rev 2018; 98:2133-2223. [PMID: 30067154 PMCID: PMC6170977 DOI: 10.1152/physrev.00063.2017] [Citation(s) in RCA: 1359] [Impact Index Per Article: 226.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/22/2018] [Accepted: 03/24/2018] [Indexed: 12/15/2022] Open
Abstract
The 1921 discovery of insulin was a Big Bang from which a vast and expanding universe of research into insulin action and resistance has issued. In the intervening century, some discoveries have matured, coalescing into solid and fertile ground for clinical application; others remain incompletely investigated and scientifically controversial. Here, we attempt to synthesize this work to guide further mechanistic investigation and to inform the development of novel therapies for type 2 diabetes (T2D). The rational development of such therapies necessitates detailed knowledge of one of the key pathophysiological processes involved in T2D: insulin resistance. Understanding insulin resistance, in turn, requires knowledge of normal insulin action. In this review, both the physiology of insulin action and the pathophysiology of insulin resistance are described, focusing on three key insulin target tissues: skeletal muscle, liver, and white adipose tissue. We aim to develop an integrated physiological perspective, placing the intricate signaling effectors that carry out the cell-autonomous response to insulin in the context of the tissue-specific functions that generate the coordinated organismal response. First, in section II, the effectors and effects of direct, cell-autonomous insulin action in muscle, liver, and white adipose tissue are reviewed, beginning at the insulin receptor and working downstream. Section III considers the critical and underappreciated role of tissue crosstalk in whole body insulin action, especially the essential interaction between adipose lipolysis and hepatic gluconeogenesis. The pathophysiology of insulin resistance is then described in section IV. Special attention is given to which signaling pathways and functions become insulin resistant in the setting of chronic overnutrition, and an alternative explanation for the phenomenon of ‟selective hepatic insulin resistanceˮ is presented. Sections V, VI, and VII critically examine the evidence for and against several putative mediators of insulin resistance. Section V reviews work linking the bioactive lipids diacylglycerol, ceramide, and acylcarnitine to insulin resistance; section VI considers the impact of nutrient stresses in the endoplasmic reticulum and mitochondria on insulin resistance; and section VII discusses non-cell autonomous factors proposed to induce insulin resistance, including inflammatory mediators, branched-chain amino acids, adipokines, and hepatokines. Finally, in section VIII, we propose an integrated model of insulin resistance that links these mediators to final common pathways of metabolite-driven gluconeogenesis and ectopic lipid accumulation.
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Affiliation(s)
- Max C Petersen
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
| | - Gerald I Shulman
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
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Lee YH, Kweon SS, Choi JS, Nam HS, Park KS, Choi SW, Oh SH, Kim SA, Shin MH. A Gender-Specific Association between Self-Reported Snoring and Hemoglobin A1c Levels in a General Population without Type 2 Diabetes Mellitus. Yonsei Med J 2017; 58:1152-1159. [PMID: 29047239 PMCID: PMC5653480 DOI: 10.3349/ymj.2017.58.6.1152] [Citation(s) in RCA: 7] [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: 05/10/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 01/26/2023] Open
Abstract
PURPOSE We explored whether a gender difference was evident in terms of the associations of snoring with hemoglobin A1c (HbA1c) and homeostatic model assessment-insulin resistance (HOMA-IR) levels in a healthy population without type 2 diabetes mellitus (DM). MATERIALS AND METHODS We analyzed 2706 males and 4080 females who participated in the baseline survey of the Namwon Study. In terms of self-reported snoring frequency, participants were classified as non-snorers or occasional (1-3 days/week), frequent (4-6 days/week), or constant (7 days/week) snorers. Participants with DM, defined as a fasting blood glucose level ≥126 mg/dL and/or use of insulin or hypoglycemic medication, were excluded from the analysis. RESULTS In females, the fully adjusted mean (95% confidence interval) HbA1c levels in non-snorers and in occasional, frequent, and constant snorers were 5.53% (5.47-5.59%), 5.53% (5.47-5.59%), 5.57% (5.49-5.64%), and 5.57% (5.51-5.64%), respectively, reflecting a dose-response relationship (p trend=0.004). Compared with female non-snorers, the risk of an elevated HbA1c level (top quintile, ≥5.9%) in constant snorers remained significant (odds ratio 1.30, 95% confidence interval 1.02-1.66) after full adjustment. In addition, in females, a significant linear trend in HbA1c level odds ratio by increased snoring frequency was apparent (p trend=0.019 in model 3). In contrast, no significant association between snoring frequency and HbA1c level was identified in males. No significant association between snoring frequency and HOMA-IR was detected in either gender. CONCLUSION We discovered a gender-specific association between snoring and HbA1c level in a healthy, community-dwelling population free of DM.
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Affiliation(s)
- Young Hoon Lee
- Department of Preventive Medicine & Institute of Wonkwang Medical Science, Wonkwang University School of Medicine, Iksan, Korea
- Regional Cardiocerebrovascular Center, Wonkwang University Hospital, Iksan, Korea
| | - Sun Seog Kweon
- Department of Preventive Medicine, Chonnam National University Medical School, Hwasun, Korea
- Jeonnam Regional Cancer Center, Chonnam National University Hwasun Hospital, Hwasun, Korea
| | - Jin Su Choi
- Department of Preventive Medicine, Chonnam National University Medical School, Hwasun, Korea
| | - Hae Sung Nam
- Department of Preventive Medicine, Chungnam National University College of Medicine, Daejeon, Korea
| | - Kyeong Soo Park
- Department of Preventive Medicine, Seonam University College of Medicine, Namwon, Korea
| | - Seong Woo Choi
- Department of Preventive Medicine, Chosun University Medical School, Gwangju, Korea
| | - Su Hyun Oh
- Department of Preventive Medicine, Chonnam National University Medical School, Hwasun, Korea
| | - Sun A Kim
- Department of Preventive Medicine, Chonnam National University Medical School, Hwasun, Korea
| | - Min Ho Shin
- Department of Preventive Medicine, Chonnam National University Medical School, Hwasun, Korea
- Center for Creative Biomedical Scientists, Chonnam National University, Gwangju, Korea.
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15
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Murphy J, Moullec G, Santosa S. Factors associated with adipocyte size reduction after weight loss interventions for overweight and obesity: a systematic review and meta-regression. Metabolism 2017; 67:31-40. [PMID: 28081776 DOI: 10.1016/j.metabol.2016.09.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 09/08/2016] [Accepted: 09/26/2016] [Indexed: 02/07/2023]
Abstract
AIMS Enlarged adipocytes are a prime feature of adipose tissue dysfunction, and may be an appropriate target to decrease disease risk in obesity. We aimed to assess the change in adipocyte size in response to lifestyle and surgical weight loss interventions for overweight or obesity; and to explore whether certain participant and intervention characteristics influence this response. METHODS We systematically searched MEDLINE, EMBASE, CINAHL and Cochrane electronic databases to identify weight loss studies that quantified adipocyte size before and after the intervention. Using meta-regression analysis, we assessed the independent effects of weight loss, age, sex, adipocyte region, and intervention type (surgical vs. lifestyle) on adipocyte size reduction. We repeated the model as a sensitivity analysis including only the lifestyle interventions. RESULTS Thirty-five studies met our eligibility criteria. In our main model, every 1.0% weight loss was associated with a 0.64% reduction in adipocyte size (p=0.003); and adipocytes from the upper body decreased 5% more in size than those in the lower body (p=0.009). These relationships were no longer significant when focusing only on lifestyle interventions. Moreover, age, sex and intervention type did not independently affect adipocyte size reduction in either model. CONCLUSIONS Weight loss in obese individuals is consistently associated with a decrease in adipocyte size that is more pronounced in upper-body adipocytes. It remains to be clarified how biological differences and intervention characteristics influence this relationship, and whether it corresponds with reductions in other aspects of adipose tissue dysfunction and disease risk.
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Affiliation(s)
- Jessica Murphy
- Department of Exercise Science, Concordia University, 7141 Sherbrooke St. W., Montreal, Quebec, Canada, H4B 1R6; Nutrition, Obesity and Metabolism Laboratory, PERFORM Centre, Concordia University, 7200 Sherbrooke St. W., Montreal, Quebec, Canada, H4B 1R6; Centre de Recherche - Axe Maladies Chroniques, Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Ile-de-Montréal, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin Blvd. W., Montreal, Quebec, Canada, H4J 1C5
| | - Grégory Moullec
- Centre de Recherche - Axe Maladies Chroniques, Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Ile-de-Montréal, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin Blvd. W., Montreal, Quebec, Canada, H4J 1C5; École de Santé Publique - Département de Médecine Sociale et Preventive, Université de Montréal, 7101 du Parc Ave., Montreal, Quebec, Canada, H3N 1X9
| | - Sylvia Santosa
- Department of Exercise Science, Concordia University, 7141 Sherbrooke St. W., Montreal, Quebec, Canada, H4B 1R6; Nutrition, Obesity and Metabolism Laboratory, PERFORM Centre, Concordia University, 7200 Sherbrooke St. W., Montreal, Quebec, Canada, H4B 1R6; Centre de Recherche - Axe Maladies Chroniques, Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Ile-de-Montréal, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin Blvd. W., Montreal, Quebec, Canada, H4J 1C5.
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16
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Yan YZ, Ma RL, Zhang JY, He J, Ma JL, Pang HR, Mu LT, Ding YS, Guo H, Zhang M, Liu JM, Rui DS, Wang K, Guo SX. Association of Insulin Resistance with Glucose and Lipid Metabolism: Ethnic Heterogeneity in Far Western China. Mediators Inflamm 2016; 2016:3825037. [PMID: 28100934 PMCID: PMC5215258 DOI: 10.1155/2016/3825037] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/11/2016] [Accepted: 11/03/2016] [Indexed: 02/01/2023] Open
Abstract
Objective. To study the relationships between IR and glucose and lipid metabolism in far western China and these relationships' ethnic heterogeneity. Methods. From the baseline survey, 419 Uygur cases, 331 Kazak cases, and 220 Han cases were randomly selected, resulting in a total of 970 cases for study. FINS concentration was measured by radioimmunoassay. Results. (1) In the Kazak population, IR was correlated with hyperglycemia; high levels of TC, TG, and LDL-C; and low levels of HDL-C and abdominal obesity (all P < 0.05). (2) In the Uygur population, the influence of IR on hyperglycemia and abdominal obesity was the greatest. In the Kazak population, IR was associated with hyperglycemia most closely. In the Han population, IR may have had an impact on the incidence of low HDL-C levels. (3) After adjusting for sex, age, smoking status, and alcohol consumption, IR was still associated with anomalies in the metabolism of the Uygur, Kazak, and Han populations. Conclusion. IR was involved in the process of glucose and lipid metabolism, and its degree of involvement differed among the ethnicities studied. We could consider reducing the occurrence of abnormal glucose and lipid metabolism by controlling IR and aiming to reduce the prevalence of metabolic syndrome and related diseases.
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Affiliation(s)
- Yi-Zhong Yan
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Ru-Lin Ma
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Jing-Yu Zhang
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Jia He
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Jiao-Long Ma
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Hong-Rui Pang
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - La-Ti Mu
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Yu-Song Ding
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
- Department of Pathology and Key Laboratory of Xinjiang Endemic and Ethnic Diseases (Ministry of Education), Shihezi University School of Medicine, Shihezi 832000, China
| | - Heng Guo
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Mei Zhang
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Jia-Ming Liu
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Dong-Sheng Rui
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Kui Wang
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
| | - Shu-Xia Guo
- Department of Preventive Medicine, University of Shihezi, Shihezi 832000, China
- Department of Pathology and Key Laboratory of Xinjiang Endemic and Ethnic Diseases (Ministry of Education), Shihezi University School of Medicine, Shihezi 832000, China
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17
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Simon SF, Taylor CG. Dietary Zinc Supplementation Attenuates Hyperglycemia in db/db Mice. Exp Biol Med (Maywood) 2016; 226:43-51. [PMID: 11368237 DOI: 10.1177/153537020122600107] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Although zinc (Zn) deficiency has been associated with insulin resistance, and altered Zn metabolism (e.g., hyperzincuria, low-normal plasma Zn concentrations) may be present in diabetes, the potential effects of Zn on modulation of insulin action in Type II diabetes have not been established. The objective of this study was to compare the effects of dietary Zn deficiency and Zn supplementation on glycemic control in db/db mice. Weanling db/db mice and lean littermate controls were fed Zn-deficient (3 ppm Zn; dbZD and InZD groups), Zn-adequate control (30 ppm Zn; dbC and InC groups) or Zn-supplemented (300 ppm Zn; dbZS and InZS groups) diets for 6 weeks. Mice were assessed for Zn status, serum and urinary indices of diabetes, and gastrocnemius insulin receptor concentration and tyrosine kinase activity. Fasting serum glucose concentrations were significantly lower in the dbZS group compared with the dbZD group (19.3 ± 2.9 and 27.9 ± 4.1 mM, respectively), whereas the dbC mice had an intermediate value. There was a negative correlation between femur Zn and serum glucose concentrations (r = −0.59 for lean mice, P = 0.007). The dbZS group had higher pancreatic Zn and lower circulating insulin concentrations than dbZC mice. Insulin-stimulated tyrosine kinase activity in gastrocnemius muscle was higher in the db/db genotype, and insulin receptor concentration was not altered. In summary, dietary Zn supplementation attenuated hyperglycemia and hyperinsulinemia in db/db mice, suggesting that the roles of Zn in pancreatic function and peripheral tissue glucose uptake need to be further investigated.
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Affiliation(s)
- S F Simon
- Department of Food and Nutrition, University of Manitoba, Winnipeg, Canada
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18
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Tsirona S, Katsaros F, Bargiota A, Polyzos SA, Arapoglou G, Koukoulis GN. Prevalence and determinants of type 2 diabetes mellitus in a Greek adult population. Hormones (Athens) 2016; 15:88-98. [PMID: 27086683 DOI: 10.1007/bf03401407] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/10/2016] [Indexed: 12/30/2022]
Abstract
The prevalence of diabetes mellitus (DM) is increasing worldwide reaching epidemic proportions. The aim of the present study was to estimate the prevalence of DM in Thessaly, a large region of Central Greece, and to extrapolate our results to the population of the entire country. A random sample of 805 adults (421 females and 384 men) living in Thessaly, aged 18-80 years, was surveyed. After completing a questionnaire about health status and a thorough physical examination, a blood sample was obtained from each participant for biochemical analysis. Participants with fasting glucose levels between 100-125 mg/dl underwent an oral glucose tolerance test (OGTT). A second survey was also conducted, via telephone call-interviews, in a randomly selected sample age- and sex-stratified to the country's adult population in order to extrapolate the DM data from Thessaly to the whole country. The frequency of DM based on patient history and fasting blood glucose levels was 6.96%, comparable to that observed in the telephone-based nationwide survey (7.38%, p=0.669). However, after the OGTT an additional 3.72% of the population had undiagnosed DM, increasing DM prevalence to 10.68% (age adjusted 11.77%). The prevalence of pre-diabetes was 8.70%, with impaired fasting glucose at 5.84% and impaired glucose tolerance at 2.86%. The prevalence of DM was significantly higher in men (14.58%) than in women (7.13%, p<0.001), increased with age in both sexes and was more prevalent in hypertensive (p<0.001) and obese subjects (p=0.001) and in those living in rural areas (p=0.003). In the multiple logistic regression analysis, significant predictors of pre-diabetes and DM together were age, homeostasis model of assessment of insulin resistance (HOMA-IR), alcohol consumption and educational status, whereas those of DM alone were age, HOMA-IR and triglycerides. Extrapolating our data to the whole country, the age-adjusted prevalence of DM was estimated at 11.97% (men 13.98%, women 9.25%), clearly indicating a major public health problem.
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Affiliation(s)
- Sofia Tsirona
- Department of Endocrinology and Metabolic Diseases, University Hospital, School of Medicine, University of Thessaly, Biopolis, Larissa, Greece
| | - Fotis Katsaros
- Department of Endocrinology and Metabolic Diseases, University Hospital, School of Medicine, University of Thessaly, Biopolis, Larissa, Greece
| | - Alexandra Bargiota
- Department of Endocrinology and Metabolic Diseases, University Hospital, School of Medicine, University of Thessaly, Biopolis, Larissa, Greece
| | - Stergios A Polyzos
- Department of Endocrinology and Metabolic Diseases, University Hospital, School of Medicine, University of Thessaly, Biopolis, Larissa, Greece
| | - George Arapoglou
- Department of Endocrinology and Metabolic Diseases, University Hospital, School of Medicine, University of Thessaly, Biopolis, Larissa, Greece
| | - George N Koukoulis
- Department of Endocrinology and Metabolic Diseases, University Hospital, School of Medicine, University of Thessaly, Biopolis, Larissa, Greece
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19
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Carnagarin R, Dharmarajan AM, Dass CR. Molecular aspects of glucose homeostasis in skeletal muscle--A focus on the molecular mechanisms of insulin resistance. Mol Cell Endocrinol 2015; 417:52-62. [PMID: 26362689 DOI: 10.1016/j.mce.2015.09.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 09/02/2015] [Indexed: 01/14/2023]
Abstract
Among all the varied actions of insulin, regulation of glucose homeostasis is the most critical and intensively studied. With the availability of glucose from nutrient metabolism, insulin action in muscle results in increased glucose disposal via uptake from the circulation and storage of excess, thereby maintaining euglycemia. This major action of insulin is executed by redistribution of the glucose transporter protein, GLUT4 from intracellular storage sites to the plasma membrane and storage of glucose in the form of glycogen which also involves modulation of actin dynamics that govern trafficking of all the signal proteins of insulin signal transduction. The cellular mechanisms responsible for these trafficking events and the defects associated with insulin resistance are largely enigmatic, and this review provides a consolidated overview of the various molecular mechanisms involved in insulin-dependent glucose homeostasis in skeletal muscle, as insulin resistance at this major peripheral site impacts whole body glucose homeostasis.
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Affiliation(s)
- Revathy Carnagarin
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia
| | - Arun M Dharmarajan
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Biomedical Science, Curtin University, Bentley 6102, Australia
| | - Crispin R Dass
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia.
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20
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Park S, Sadanala KC, Kim EK. A Metabolomic Approach to Understanding the Metabolic Link between Obesity and Diabetes. Mol Cells 2015; 38:587-96. [PMID: 26072981 PMCID: PMC4507023 DOI: 10.14348/molcells.2015.0126] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 05/22/2015] [Accepted: 05/26/2015] [Indexed: 12/19/2022] Open
Abstract
Obesity and diabetes arise from an intricate interplay between both genetic and environmental factors. It is well recognized that obesity plays an important role in the development of insulin resistance and diabetes. Yet, the exact mechanism of the connection between obesity and diabetes is still not completely understood. Metabolomics is an analytical approach that aims to detect and quantify small metabolites. Recently, there has been an increased interest in the application of metabolomics to the identification of disease biomarkers, with a number of well-known biomarkers identified. Metabolomics is a potent approach to unravel the intricate relationships between metabolism, obesity and progression to diabetes and, at the same time, has potential as a clinical tool for risk evaluation and monitoring of disease. Moreover, metabolomics applications have revealed alterations in the levels of metabolites related to obesity-associated diabetes. This review focuses on the part that metabolomics has played in elucidating the roles of metabolites in the regulation of systemic metabolism relevant to obesity and diabetes. It also explains the possible metabolic relation and association between the two diseases. The metabolites with altered profiles in individual disorders and those that are specifically and similarly altered in both disorders are classified, categorized and summarized.
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Affiliation(s)
- Seokjae Park
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu 711-873,
Korea
- Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science & Technology, Daegu 711-873,
Korea
| | - Krishna Chaitanya Sadanala
- Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science & Technology, Daegu 711-873,
Korea
| | - Eun-Kyoung Kim
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu 711-873,
Korea
- Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science & Technology, Daegu 711-873,
Korea
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21
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Alejandro EU, Gregg B, Blandino-Rosano M, Cras-Méneur C, Bernal-Mizrachi E. Natural history of β-cell adaptation and failure in type 2 diabetes. Mol Aspects Med 2014; 42:19-41. [PMID: 25542976 DOI: 10.1016/j.mam.2014.12.002] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 11/04/2014] [Accepted: 12/05/2014] [Indexed: 02/07/2023]
Abstract
Type 2 diabetes mellitus (T2D) is a complex disease characterized by β-cell failure in the setting of insulin resistance. The current evidence suggests that genetic predisposition, and environmental factors can impair the capacity of the β-cells to respond to insulin resistance and ultimately lead to their failure. However, genetic studies have demonstrated that known variants account for less than 10% of the overall estimated T2D risk, suggesting that additional unidentified factors contribute to susceptibility of this disease. In this review, we will discuss the different stages that contribute to the development of β-cell failure in T2D. We divide the natural history of this process in three major stages: susceptibility, β-cell adaptation and β-cell failure, and provide an overview of the molecular mechanisms involved. Further research into mechanisms will reveal key modulators of β-cell failure and thus identify possible novel therapeutic targets and potential interventions to protect against β-cell failure.
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Affiliation(s)
- Emilyn U Alejandro
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, Brehm Center for Diabetes Research, University of Michigan, Ann Arbor, MI, USA
| | - Brigid Gregg
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Manuel Blandino-Rosano
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, Brehm Center for Diabetes Research, University of Michigan, Ann Arbor, MI, USA
| | - Corentin Cras-Méneur
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, Brehm Center for Diabetes Research, University of Michigan, Ann Arbor, MI, USA
| | - Ernesto Bernal-Mizrachi
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, Brehm Center for Diabetes Research, University of Michigan, Ann Arbor, MI, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
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22
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Feraco A, Armani A, Mammi C, Fabbri A, Rosano GMC, Caprio M. Role of mineralocorticoid receptor and renin-angiotensin-aldosterone system in adipocyte dysfunction and obesity. J Steroid Biochem Mol Biol 2013; 137:99-106. [PMID: 23454117 DOI: 10.1016/j.jsbmb.2013.02.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 02/07/2013] [Accepted: 02/20/2013] [Indexed: 12/13/2022]
Abstract
The mineralocorticoid receptor (MR) classically mediates aldosterone effects on salt homeostasis and blood pressure regulation in epithelial target tissues. In recent years, functional MRs have been identified in non classical targets of aldosterone actions, in particular in adipose tissue, where they mediate the effects of aldosterone and glucocorticoids in the control of adipogenesis, adipose expansion and its pro-inflammatory capacity. In this context, inappropriate MR activation has been demonstrated to be a causal factor in several pathologic conditions such as vascular inflammation, endothelial dysfunction, insulin resistance and obesity. The aim of this review is to summarize the latest developments in this rapidly developing field, and will focus on the role of MR and renin-angiotensin-aldosterone system (RAAS) as potential leading characters in the early steps of adipocyte dysfunction and obesity. Indeed modulation of MR activity in adipose tissue has promise as a novel therapeutic approach to treat obesity and its related metabolic complications. This article is part of a Special Issue entitled 'CSR 2013'.
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23
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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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24
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Molecular Mechanisms of Insulin Resistance in Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 771:240-51. [DOI: 10.1007/978-1-4614-5441-0_19] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Diamanti-Kandarakis E, Dunaif A. Insulin resistance and the polycystic ovary syndrome revisited: an update on mechanisms and implications. Endocr Rev 2012; 33:981-1030. [PMID: 23065822 PMCID: PMC5393155 DOI: 10.1210/er.2011-1034] [Citation(s) in RCA: 1041] [Impact Index Per Article: 86.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Polycystic ovary syndrome (PCOS) is now recognized as an important metabolic as well as reproductive disorder conferring substantially increased risk for type 2 diabetes. Affected women have marked insulin resistance, independent of obesity. This article summarizes the state of the science since we last reviewed the field in the Endocrine Reviews in 1997. There is general agreement that obese women with PCOS are insulin resistant, but some groups of lean affected women may have normal insulin sensitivity. There is a post-binding defect in receptor signaling likely due to increased receptor and insulin receptor substrate-1 serine phosphorylation that selectively affects metabolic but not mitogenic pathways in classic insulin target tissues and in the ovary. Constitutive activation of serine kinases in the MAPK-ERK pathway may contribute to resistance to insulin's metabolic actions in skeletal muscle. Insulin functions as a co-gonadotropin through its cognate receptor to modulate ovarian steroidogenesis. Genetic disruption of insulin signaling in the brain has indicated that this pathway is important for ovulation and body weight regulation. These insights have been directly translated into a novel therapy for PCOS with insulin-sensitizing drugs. Furthermore, androgens contribute to insulin resistance in PCOS. PCOS may also have developmental origins due to androgen exposure at critical periods or to intrauterine growth restriction. PCOS is a complex genetic disease, and first-degree relatives have reproductive and metabolic phenotypes. Several PCOS genetic susceptibility loci have been mapped and replicated. Some of the same susceptibility genes contribute to disease risk in Chinese and European PCOS populations, suggesting that PCOS is an ancient trait.
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Yan J, Zhao Y, Suo S, Liu Y, Zhao B. Green tea catechins ameliorate adipose insulin resistance by improving oxidative stress. Free Radic Biol Med 2012; 52:1648-57. [PMID: 22330066 DOI: 10.1016/j.freeradbiomed.2012.01.033] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 01/26/2012] [Accepted: 01/30/2012] [Indexed: 01/14/2023]
Abstract
Epidemiological data have suggested that drinking green tea is negatively associated with diabetes, and adipose oxidative stress may have a central role in causing insulin resistance, according to recent findings. The aim of this work is to elucidate a new mechanism for green tea's anti-insulin resistance effect. We used obese KK-ay mice, high-fat diet-induced obese rats, and induced insulin resistant 3T3-L1 adipocytes as models. Insulin sensitivity and adipose reactive oxidative species (ROS) levels were detected in animals and adipocytes. The oxidative stress assay and glucose uptake ability assay were performed, and the effects of EGCG on insulin signals were detected. Green tea catechins (GTCs) significantly decreased glucose levels and increased glucose tolerance in animals. GTCs reduced ROS content in both models of animal and adipocytes. EGCG attenuated dexamethasone and TNF-α promoted ROS generation and increased glucose uptake ability. EGCG also decreased JNK phosphorylation and promoted GLUT-4 translocation. EGCG and GTCs could improve adipose insulin resistance, and exact this effect on their ROS scavenging functions.
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Affiliation(s)
- Jingqi Yan
- State Key Laboratory of Brain & Cognitive Sciences, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, People's Republic of China
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Wang T, Li M, Chen B, Xu M, Xu Y, Huang Y, Lu J, Chen Y, Wang W, Li X, Liu Y, Bi Y, Lai S, Ning G. Urinary bisphenol A (BPA) concentration associates with obesity and insulin resistance. J Clin Endocrinol Metab 2012; 97:E223-7. [PMID: 22090277 DOI: 10.1210/jc.2011-1989] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CONTEXT Bisphenol A (BPA) is one of the world's highest-volume chemicals in use today. Previous studies have suggested BPA disturbs body weight regulation and promotes obesity and insulin resistance. But epidemiological data in humans were limited. OBJECTIVE Our objective was to determine whether BPA associates with obesity and insulin resistance. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study included 3390 adults aged 40 yr or older, in Songnan Community, Baoshan District, Shanghai, China. MAIN OUTCOME MEASURES Questionnaire, clinical and biochemical measurements, and urinary BPA concentration were determined. Generalized overweight was defined as body mass index (BMI) of 24 to less than 28 kg/m(2) and obesity was defined as BMI of 28 kg/m(2) or higher. Abdominal obesity was defined as waist circumference at least 90 cm for men and at least 85 cm for women. Insulin resistance was defined as the index of homeostasis model assessment of insulin resistance higher than 2.50. RESULTS The participants in the highest quartile of BPA had the highest prevalence of generalized obesity [odds ratio (OR) = 1.50; 95% confidence interval (CI) = 1.15-1.97], abdominal obesity (OR = 1.28; 95% CI = 1.03-1.60), and insulin resistance (OR = 1.37; 95% CI = 1.06-1.77). In participants with BMI under 24 kg/m(2), compared with the lowest quartile, the highest quartile of BPA increased the prevalence of insulin resistance by 94% (OR = 1.94; 95% CI = 1.20-3.14), but this association was not observed in those with BMI of 24 kg/m(2) or higher. CONCLUSIONS BPA was positively associated with generalized obesity, abdominal obesity, and insulin resistance in middle-aged and elderly Chinese adults.
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Affiliation(s)
- Tiange Wang
- Key Laboratory for Endocrine and Metabolic Diseases of Ministry of Health, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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Dhote V, Joharapurkar A, Kshirsagar S, Dhanesha N, Patel V, Patel A, Raval S, Jain M. Inhibition of microsomal triglyceride transfer protein improves insulin sensitivity and reduces atherogenic risk in Zucker fatty rats. Clin Exp Pharmacol Physiol 2011; 38:338-44. [PMID: 21401695 DOI: 10.1111/j.1440-1681.2011.05513.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
1. Insulin-resistant states are commonly associated with a significantly higher risk of atherosclerosis. Insulin resistance has also been correlated with enhanced very low-density lipoprotein (VLDL) production, which is exacerbated by increased intestinal lipid synthesis and insulin-stimulated de novo lipogenesis. Microsomal triglyceride transfer protein (MTP) catalyses the critical step in the synthesis and secretion of VLDL and chylomicrons. The purpose of the present study was to test the hypothesis that chronic inhibition of MTP with a small molecule inhibitor would improve insulin sensitivity and reduce atherogenic risk in a genetic model of diabetic dyslipidaemia. 2. The in vivo activity of BMS-201038, a potent inhibitor of MTP, was evaluated in a model of hypertriglyceridemia induced by Triton WR1339 and corn oil in Zucker fatty rats. Triglyceride secretion rate was significantly reduced by a single dose of BMS-201038 by 35% at 0.3 mg/kg and 47% at 1 mg/kg, respectively. 3. Another group of Zucker fatty rats was dosed orally with BMS-201038 (0.3 and 1 mg/kg) for 14 days. Serum levels of triglycerides were reduced by 71% and 87%, non-esterified free fatty acids were reduced by 33% and 40%, and low-density lipoproteins by 26% and 29%, by 0.3 mg/kg and 1 mg/kg dose of BMS-201038, respectively. These serum lipid changes were accompanied by significant improvements in glucose tolerance and insulin sensitivity. In addition, lipid peroxidation in liver was reduced by 59% and 61%, and superoxide dismutase activity was increased by 11% and 45% by 0.3 mg/kg and 1 mg/kg dose of BMS-201038, respectively. Similar beneficial changes were found in aorta as well. 4. The present study provides evidence that inhibition of MTP with a small molecule inhibitor significantly improves dyslipidaemia associated with insulin resistance and reduces the atherosclerotic risk.
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Affiliation(s)
- Vipin Dhote
- Departments of Pharmacology and Toxicology, Zydus Research Centre, Cadila Healthcare Limited, Ahmedabad, Gujarat, India
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DeFronzo RA. Insulin resistance, lipotoxicity, type 2 diabetes and atherosclerosis: the missing links. The Claude Bernard Lecture 2009. Diabetologia 2010; 53:1270-87. [PMID: 20361178 PMCID: PMC2877338 DOI: 10.1007/s00125-010-1684-1] [Citation(s) in RCA: 563] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 12/22/2009] [Indexed: 12/15/2022]
Abstract
Insulin resistance is a hallmark of type 2 diabetes mellitus and is associated with a metabolic and cardiovascular cluster of disorders (dyslipidaemia, hypertension, obesity [especially visceral], glucose intolerance, endothelial dysfunction), each of which is an independent risk factor for cardiovascular disease (CVD). Multiple prospective studies have documented an association between insulin resistance and accelerated CVD in patients with type 2 diabetes, as well as in non-diabetic individuals. The molecular causes of insulin resistance, i.e. impaired insulin signalling through the phosphoinositol-3 kinase pathway with intact signalling through the mitogen-activated protein kinase pathway, are responsible for the impairment in insulin-stimulated glucose metabolism and contribute to the accelerated rate of CVD in type 2 diabetes patients. The current epidemic of diabetes is being driven by the obesity epidemic, which represents a state of tissue fat overload. Accumulation of toxic lipid metabolites (fatty acyl CoA, diacylglycerol, ceramide) in muscle, liver, adipocytes, beta cells and arterial tissues contributes to insulin resistance, beta cell dysfunction and accelerated atherosclerosis, respectively, in type 2 diabetes. Treatment with thiazolidinediones mobilises fat out of tissues, leading to enhanced insulin sensitivity, improved beta cell function and decreased atherogenesis. Insulin resistance and lipotoxicity represent the missing links (beyond the classical cardiovascular risk factors) that help explain the accelerated rate of CVD in type 2 diabetic patients.
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Affiliation(s)
- R A DeFronzo
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive-MSC 7886, San Antonio, TX, 78229, USA.
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Pathogenesis of insulin resistance in skeletal muscle. J Biomed Biotechnol 2010; 2010:476279. [PMID: 20445742 PMCID: PMC2860140 DOI: 10.1155/2010/476279] [Citation(s) in RCA: 375] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 01/20/2010] [Indexed: 12/16/2022] Open
Abstract
Insulin resistance in skeletal muscle is manifested by decreased insulin-stimulated glucose uptake and results from impaired insulin signaling and multiple post-receptor intracellular defects including impaired glucose transport, glucose phosphorylation, and reduced glucose oxidation and glycogen synthesis. Insulin resistance is a core defect in type 2 diabetes, it is also associated with obesity and the metabolic syndrome. Dysregulation of fatty acid metabolism plays a pivotal role in the pathogenesis of insulin resistance in skeletal muscle. Recent studies have reported a mitochondrial defect in oxidative phosphorylation in skeletal muscle in variety of insulin resistant states. In this review, we summarize the cellular and molecular defects that contribute to the development of insulin resistance in skeletal muscle.
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Au WS, Lu LW, Tam S, Ko OKH, Chow BKC, He ML, Ng SS, Yeung CM, Liu CC, Kung HF, Lin MC. Pluronic L-81 ameliorates diabetic symptoms in db/db mice through transcriptional regulation of microsomal triglyceride transfer protein. World J Gastroenterol 2009; 15:2987-94. [PMID: 19554651 PMCID: PMC2702106 DOI: 10.3748/wjg.15.2987] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To test whether oral L-81 treatment could improve the condition of mice with diabetes and to investigate how L-81 regulates microsomal triglyceride transfer protein (MTP) activity in the liver.
METHODS: Genetically diabetic (db/db) mice were fed on chow supplemented with or without L-81 for 4 wk. The body weight, plasma glucose level, plasma lipid profile, and adipocyte volume of the db/db mice were assessed after treatment. Toxicity of L-81 was also evaluated. To understand the molecular mechanism, HepG2 cells were treated with L-81 and the effects on apolipoprotein B (apoB) secretion and mRNA level of the MTP gene were assessed.
RESULTS: Treatment of db/db mice with L-81 significantly reduced and nearly normalized their body weight, hyperphagia and polydipsia. L-81 also markedly decreased the fasting plasma glucose level, improved glucose tolerance, and attenuated the elevated levels of plasma cholesterol and triglyceride. At the effective dosage, little toxicity was observed. Treatment of HepG2 cells with L-81 not only inhibited apoB secretion, but also significantly decreased the mRNA level of the MTP gene. Similar to the action of insulin, L-81 exerted its effect on the MTP promoter.
CONCLUSION: L-81 represents a promising candidate in the development of a selective insulin-mimetic molecule and an anti-diabetic agent.
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32
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Giaccari A, Sorice G, Muscogiuri G. Glucose toxicity: the leading actor in the pathogenesis and clinical history of type 2 diabetes - mechanisms and potentials for treatment. Nutr Metab Cardiovasc Dis 2009; 19:365-377. [PMID: 19428228 DOI: 10.1016/j.numecd.2009.03.018] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 02/18/2009] [Accepted: 03/11/2009] [Indexed: 01/09/2023]
Abstract
AIM Although it is now well established that the deleterious effects of chronic hyperglycaemia (i.e., glucose toxicity) play an important role in the progressive impairment of insulin secretion and sensitivity, the two major actors of the pathogenesis of type 2 diabetes mellitus, the precise biochemical and molecular mechanisms responsible for the defects induced by glucose toxicity still remain to be defined. DATA SYNTHESIS here we will briefly report on convincing evidence that glucose toxicity acts through oxidative stress, modifications in the exosamine pathway, protein kinase C and others. After inducing or contributing to the genesis of type 2 diabetes, these same mechanisms are considered responsible for the appearance and worsening of diabetic specific microvascular complications, while its role in increasing the risk of cardiovascular diseases is less clear. Recent intervention studies (ADVANCE, ACCORD, VADT), conducted to evaluate the effects of strict glycaemic control, apparently failed to demonstrate an effect of glucose toxicity on cardiovascular diseases, at least in secondary prevention or when diabetes is present for a prolonged time. The re-examination, 20 years later, of the population studied in the UKPDS study, however, clearly demonstrated that the earliest is the strict glycaemic control reached, the lowest is the incidence of cardiovascular diseases observed, including myocardial infarction. CONCLUSION The acquaintance of the role of glucose toxicity should strongly influence the usual therapeutic choices and glycaemic targets where the reduced or absent risk of hypoglycaemia, durability of action, and data on prolonged safety should be the preferred characteristics of the drug of choice in the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- A Giaccari
- Endocrinology, Catholic University, Rome, Italy.
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33
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Guilherme A, Tesz GJ, Guntur KVP, Czech MP. Tumor necrosis factor-alpha induces caspase-mediated cleavage of peroxisome proliferator-activated receptor gamma in adipocytes. J Biol Chem 2009; 284:17082-17091. [PMID: 19321447 DOI: 10.1074/jbc.m809042200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-dependent transcription factor that acts as a primary regulator of adipogenesis and controls adipocyte metabolism and insulin action. Increased expression of tumor necrosis factor (TNFalpha) in adipose tissue of obese subjects potently suppresses the expression of PPARgamma and attenuates adipocyte functions. Here we show that PPARgamma is a substrate of caspase-3 and caspase-6 during TNFalpha receptor signaling in adipocytes, and the consequent PPARgamma cleavage disrupts its nuclear localization. TNFalpha treatment of 3T3-L1 adipocytes decreases full-length PPARgamma while increasing the level of a 45-kDa immunoreactive PPARgamma fragment. Specific inhibitors of caspase-3 and caspase-6 attenuate the cleavage of PPARgamma protein in response to TNFalpha in cultured adipocytes. Incubation of nuclear fractions with recombinant caspase-3 and caspase-6 also generates a 45-kDa PPARgamma cleavage product. Dispersion of nuclear PPARgamma to the cytoplasm in response to TNFalpha treatment occurs in parallel with detection of activated caspase-3. We suggest that activation of the caspase cascade by TNFalpha down-regulates PPARgamma protein and PPARgamma-mediated metabolic processes in adipose cells.
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Affiliation(s)
- Adilson Guilherme
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Gregory J Tesz
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Kalyani V P Guntur
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Michael P Czech
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605.
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Adipocyte dysfunctions linking obesity to insulin resistance and type 2 diabetes. Nat Rev Mol Cell Biol 2008; 9:367-77. [PMID: 18401346 DOI: 10.1038/nrm2391] [Citation(s) in RCA: 1585] [Impact Index Per Article: 99.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Acquired resistance to the action of insulin to stimulate glucose transport in skeletal muscle is associated with obesity and promotes the development of type 2 diabetes. In skeletal muscle, insulin resistance can result from high levels of circulating fatty acids that disrupt insulin signalling pathways. However, the severity of insulin resistance varies greatly among obese people. Here we postulate that this variability might reflect differences in levels of lipid-droplet proteins that promote the sequestration of fatty acids within adipocytes in the form of triglycerides, thereby lowering exposure of skeletal muscle to the inhibitory effects of fatty acids.
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Qatanani M, Lazar MA. Mechanisms of obesity-associated insulin resistance: many choices on the menu. Genes Dev 2007; 21:1443-55. [PMID: 17575046 DOI: 10.1101/gad.1550907] [Citation(s) in RCA: 502] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Obesity-associated insulin resistance is a major risk factor for type 2 diabetes and cardiovascular disease. In the past decade, a large number of endocrine, inflammatory, neural, and cell-intrinsic pathways have been shown to be dysregulated in obesity. Although it is possible that one of these factors plays a dominant role, many of these factors are interdependent, and it is likely that their dynamic interplay underlies the pathophysiology of insulin resistance. Understanding the biology of these systems will inform the search for interventions that specifically prevent or treat insulin resistance and its associated pathologies.
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Affiliation(s)
- Mohammed Qatanani
- Division of Endocrinology, Diabetes, and Metabolism, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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McGrowder D, Ragoobirsingh D, Brown P. Modulation of glucose uptake in adipose tissue by nitric oxide-generating compounds. J Biosci 2006; 31:347-54. [PMID: 17006017 DOI: 10.1007/bf02704107] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
There is increasing evidence that endogenous nitric oxide (NO) influences adipogenesis, lipolysis and insulin-stimulated glucose uptake. We investigated the effect of NO released from S-nitrosoglutathione (GSNO) and S-nitroso-N-acetylpenicillamine (SNAP) on basal and insulin-stimulated glucose uptake in adipocytes of normoglycaemic and streptozotocin (STZ)-induced diabetic rats. GSNO and SNAP at 0.2,0.5, and 1 mM brought about a concentration-dependent increase in basal and insulin-stimulated 2-deoxyglucose uptake in adipocytes of normoglycaemic and STZ-induced diabetic rats. SNAP at 1.0 mM significantly elevated basal 2-deoxyglucose uptake (115.8+/-10.4% compared with GSNO at the same concentration (116.1+/-9.4%; P less than 0.05) in STZ-induced diabetic rats. Conversely, SNAP at concentrations of 10 mM and 20 mM significantly decreased basal 2-deoxyglucose uptake by 50.0+/-4.5% and 61.5+/-7.2% respectively in adipocytes of STZ-induced diabetic rats (P less than 0.05). GSNO at concentrations of 10 mM and 20 mM also significantly decreased basal 2-deoxyglucose uptake by 50.8+/-6.4% and 55.2+/-7.8% respectively in adipocytes of STZ-induced diabetic rats (P less than 0.05). These observations indicate that NO released from GSNO and SNAP at 1 mM or less stimulates basal and insulin-stimulated glucose uptake,and at concentrations of 10 mM and 20 mM inhibits basal glucose uptake. The additive effect of GSNO or SNAP, and insulin observed in this study could be due to different mechanisms and warrants further investigation.
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Affiliation(s)
- Donovan McGrowder
- Department of Pathology, University of the West Indies, Kingston 7, Jamaica, West Indies.
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Beha A, Juretschke HP, Kuhlmann J, Neumann-Haefelin C, Belz U, Gerl M, Kramer W, Roden M, Herling AW. Muscle type-specific fatty acid metabolism in insulin resistance: an integrated in vivo study in Zucker diabetic fatty rats. Am J Physiol Endocrinol Metab 2006; 290:E989-97. [PMID: 16380389 DOI: 10.1152/ajpendo.00459.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Intramyocellular lipid content (IMCL) serves as a good biomarker of skeletal muscle insulin resistance (IR). However, intracellular fatty acid metabolites [malonyl-CoA, long-chain acyl-CoA (LCACoA)] rather than IMCL are considered to be responsible for IR. This study aimed to investigate dynamics of IMCL and fatty acid metabolites during fed-to-starved-to-refed transition in lean and obese (IR) Zucker diabetic fatty rats in the following different muscle types: soleus (oxidative), extensor digitorum longus (EDL, intermediary), and white tibialis anterior (wTA, glycolytic). In the fed state, IMCL was significantly elevated in obese compared with lean rats in all three muscle types (soleus: 304%, EDL: 333%, wTA: 394%) in the presence of elevated serum triglycerides but similar levels of free fatty acids (FFA), malonyl-CoA, and total LCACoAs. During starvation, IMCL in soleus remained relatively constant, whereas in both rat groups IMCL increased significantly in wTA and EDL after comparable dynamics of starvation-induced FFA availability. The decreases of malonyl-CoA in wTA and EDL during starvation were more pronounced in lean than in obese rats, although there were no changes in soleus muscles for both groups. The concomitant increase in IMCL with the fall of malonyl-CoA support the concept that, as a reaction to starvation-induced FFA availability, muscle will activate lipid oxidation more the lower its oxidative capacity and then store the rest as IMCL.
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MESH Headings
- 3-Hydroxyacyl CoA Dehydrogenases/metabolism
- Animals
- Blood Glucose/metabolism
- Body Weight/physiology
- Fatty Acids/analysis
- Fatty Acids/metabolism
- Fatty Acids, Nonesterified/blood
- Fatty Acids, Unsaturated/analysis
- Glucose Clamp Technique
- Glyceraldehyde-3-Phosphate Dehydrogenases/metabolism
- Glycogen Phosphorylase/metabolism
- Hexokinase/metabolism
- Insulin/blood
- Insulin Resistance/physiology
- Ketone Bodies/blood
- Lipids/analysis
- Male
- Malonyl Coenzyme A/metabolism
- Muscle Fibers, Fast-Twitch/chemistry
- Muscle Fibers, Fast-Twitch/enzymology
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/chemistry
- Muscle Fibers, Slow-Twitch/enzymology
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle, Skeletal/chemistry
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/metabolism
- Rats
- Rats, Zucker
- Triglycerides/blood
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Affiliation(s)
- Anja Beha
- Sanofi-Aventis Deutschland, Frankfurt/Main, Germany
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Szoke E, Gerich JE. Role of impaired insulin secretion and insulin resistance in the pathogenesis of type 2 diabetes mellitus. ACTA ACUST UNITED AC 2005; 31:106-12. [PMID: 15901939 DOI: 10.1007/s12019-005-0005-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Accepted: 01/31/2005] [Indexed: 01/09/2023]
Abstract
Type 2 diabetes mellitus (T2DM) is a heterogeneous disorder caused by a combination of genetic and acquired abnormalities that affect insulin sensitivity and insulin secretion. Currently available data suggest that insulin resistance is the acquired defect largely secondary to unhealthy lifestyles and that the major genetic factor is impaired insulin secretion. The latter is the result of both reduced beta-cell mass and functional abnormalities makes the beta-cell unable to compensate for increased insulin requirements caused by insulin resistance. Targeting both insulin resistance and impaired insulin secretion is therefore appropriate to prevent T2DM and to improve glycemic control in those with the disorder.
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Affiliation(s)
- Ervin Szoke
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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Quraishi I, Collins S, Pestaner JP, Harris T, Bagasra O. Role of zinc and zinc transporters in the molecular pathogenesis of diabetes mellitus. Med Hypotheses 2005; 65:887-92. [PMID: 16043303 DOI: 10.1016/j.mehy.2005.02.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Accepted: 02/10/2005] [Indexed: 11/27/2022]
Abstract
Diabetes is one of the most common chronic diseases in the United States. An estimated 18.2 million people in the US (6.3%) have diabetes; among them 2.8 million are African Americans (AAs). On average, AAs are twice as likely to have diabetes as European Americans (EAs) of similar age. AAs disproportionately suffer from various diseases in the US. Many of these diseases include hypertension, cardiovascular disease (CVD), diabetes mellitus (DM-beta predominantly Type II), and cancers of the prostate and pancreas. A number of risk factors such as smoking, a high fat diet, little physical activity, stress, and meager access to health care have been the subject of numerous investigations. However, the factor of the interaction between genetics and the environment has received very little attention in the scientific community. Of note, the content of zinc in pancreatic beta gells is among the highest in the body; however, very little is known about the uptake and storage of zinc inside these cells. We hypothesize that one of the major reason AAs disproportionally suffer from DM (as well as some other illnesses like prostate cancer, CVD and hypertension) is due to their inherent inability to transport appropriate amount of zinc in the crucial cell types that require relatively higher amount of zinc than the other cell types. In this article, we will explore in detail the possible genetic and environmental link between human zinc transporters (hZIPs) and their differential expressions in the islet beta cells from AAs as compared to other racial groups, particularly EAs, in both normal healthy individuals and diabetic patients. We hypothesize that the hZIPs play an important role in the development of diabetes, and the main reason AAs disproportionately suffer from DM (as well as other illnesses like prostate and pancreatic cancers, hypertension, and CVD) as compared to EAs may be due the low degree of expressions of the critical zinc transporters in the beta cells. Understanding the molecular events in the pathogenesis of DM with regards to regulation of zinc uptake would be critical to the evaluation of the natural history of diabetes in humans and especially in various racial groups. If a direct link between zinc transport and diabetes can be established, then a special nutritional formula, medication or other intervention might be especially designed to test the ability to decrease the incidence of this disease in DM susceptible groups, particularly in AAs.
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Affiliation(s)
- Iram Quraishi
- South Carolina Cancer Center, University of South Carolina, Columbia, SC 29203, USA
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Mooradian AD, Chehade J, Thurman JE. The role of thiazolidinediones in the treatment of patients with type 2 diabetes mellitus. ACTA ACUST UNITED AC 2005; 1:13-20. [PMID: 15765617 DOI: 10.2165/00024677-200201010-00002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diabetes mellitus is a significant and growing health concern worldwide. Unfortunately, type 2 diabetes mellitus is generally under-managed, and this may explain the increasing prevalence of diabetic complications throughout the world. The introduction of newer classes of antihyperglycemic agents should enhance the ability of clinicians to achieve optimal blood glucose control. One recent addition to the pharmacologic armamentarium is the thiazolidinedione class. The main effect of thiazolidinediones is amelioration of insulin resistance. These agents may also preserve beta-cell function, although evidence in favor of this effect is still inconclusive. The mechanism of action of thiazolidinediones is not completely understood. Similarly, the current state of knowledge cannot explain the differences in the lipid effects of pioglitazone and rosiglitazone. Thiazolidinediones are commonly used as add-on therapy for those requiring large daily doses of insulin therapy, or in addition to sulfonylurea agents and metformin for those reluctant to start insulin therapy. The potential role of thiazolidinediones as first-line therapy is now emerging. It is possible that in certain subgroups, particularly patients with renal failure, elderly individuals or those with corticosteroid-induced diabetes mellitus, the use of thiazolidinediones as a first-line therapy is justifiable. However, the lack of a long-term safety record, and the cost, would limit the widespread acceptance of this class of agents as first-line therapy.
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Affiliation(s)
- Arshag D Mooradian
- Division of Endocrinology, Saint Louis University School of Medicine, St Louis, Missouri 63104, USA.
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41
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Abstract
Type 2 diabetes is increasing worldwide in epidemic proportions. Its associated morbidity and mortality is imposing a major burden on the health care system. Based on a better understanding of the pathophysiology of glucose intolerance, clinical trials on the prevention of diabetes have been performed. It has now been demonstrated that diet and exercise, metformin, acarbose, and troglitazone can prevent or at least delay the development of diabetes in subjects with impaired glucose tolerance (IGT). It is now generally accepted that insulin resistance and beta-cell dysfunction are major factors involved in the development of diabetes. The relative contribution of insulin resistance versus beta-cell dysfunction on the pathogenesis of diabetes has aroused much debate. These two processes should be studied in relation to one another: their relationship is best described as hyperbolic in nature. When this relationship is taken into consideration, it becomes evident that subjects at risk of developing type 2 diabetes have beta-cell dysfunction before they develop glucose intolerance. Insulin resistance may be mostly explained by the presence of obesity and accelerate the progression to diabetes in subjects with the propensity to beta-cell failure. By the time hyperglycemia occurs, impairment in both insulin sensitivity and insulin secretion are present. There are still few data on insulin sensitivity and insulin secretion from the trials on the prevention of diabetes. The few data that we do have suggest that most interventions mostly have an effect on insulin resistance. By reducing insulin resistance, they protect and preserve the beta-cell function. No intervention has yet shown any direct effect on beta-cell function.
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Affiliation(s)
- J-L Chiasson
- Research Centre-CHUM-Hôtel-Dieu, 3850 St. Urbain St., Rm. 8-202, Montreal (Quebec) H2W 1T7, Canada.
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42
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Abstract
Nonalcoholic fatty liver disease (NAFLD), already the most common form of liver disease in the United States, can be expected to increase in prevalence and severity in parallel with national epidemics of obesity and type 2 diabetes. NAFLD is frequently associated with insulin resistance. While insulin resistance, and thereby hyperinsulinemia, are, in large part, metabolic consequences of obesity, the basis of diversity in severity and progression of inflammation and fibrosis is not known. Increased susceptibility to oxidative stress is likely to play a role. Several patient characteristics have been associated with more severe histological findings in patients with NAFLD, including type 2 diabetes, hypertension, age over 40 years, and higher transaminases. Liver biopsy is, however, required to accurately grade and stage NAFLD histologically. Although the natural history of NAFLD is relatively poorly defined, NAFLD is increasingly recognized as an important cause of decompensated liver disease. Weight reduction and improved insulin sensitivity are associated with improved biochemical and histological parameters of NAFLD. There are, however, no proven safe and efficacious pharmacological treatments for NAFLD.
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Affiliation(s)
- Michael Charlton
- Department of Gastroenterology and Hepatology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
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Werner ED, Lee J, Hansen L, Yuan M, Shoelson SE. Insulin Resistance Due to Phosphorylation of Insulin Receptor Substrate-1 at Serine 302. J Biol Chem 2004; 279:35298-305. [PMID: 15199052 DOI: 10.1074/jbc.m405203200] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Inhibitory serine phosphorylation is a potential molecular mechanism for insulin resistance. We have developed a new variant of the yeast two-hybrid method, referred to as disruptive yeast tri-hybrid (Y3H), to identify inhibitory kinases and sites of phosphorylation in insulin receptors (IR) and IR substrates, IRS-1. Using IR and IRS-1 as bait and prey, respectively, and c-Jun NH(2)-terminal kinase (JNK1) as the disruptor, we now show that phosphorylation of IRS-1 Ser-307, a previously identified site, is necessary but not sufficient for JNK1-mediated disruption of IR/IRS-1 binding. We further identify a new phosphorylation site, Ser-302, and show that this too is necessary for JNK1-mediated disruption. Seven additional kinases potentially linked to insulin resistance similarly block IR/IRS-1 binding in the disruptive Y3H, but through distinct Ser-302- and Ser-307-independent mechanisms. Phosphospecific antibodies that recognize sequences surrounding Ser(P)-302 or Ser(P)-307 were used to determine whether the sites were phosphorylated under relevant conditions. Phosphorylation was promoted at both sites in Fao hepatoma cells by reagents known to promote Ser/Thr phosphorylation, including the phorbol ester phorbol 12-myristate 13-acetate, anisomycin, calyculin A, and insulin. The antibodies further showed that Ser(P)-302 and Ser(P)-307 are increased in animal models of obesity and insulin resistance, including genetically obese ob/ob mice, diet-induced obesity, and upon induction of hyperinsulinemia. These findings demonstrate that phosphorylation at both Ser-302 and Ser-307 is necessary for JNK1-mediated inhibition of the IR/IRS-1 interaction and that Ser-302 and Ser-307 are phosphorylated in parallel in cultured cells and in vivo under conditions that lead to insulin resistance.
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Affiliation(s)
- Eric D Werner
- Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA
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44
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Abstract
This article provides an overview of the pathogenesis of type 2 diabetes mellitus. Discussion begins by describing normal glucose homeostasis and ingestion of a typical meal and then discusses glucose homeostasis in diabetes. Topics covered include insulin secretion in type 2 diabetes mellitus and insulin resistance, the site of insulin resistance, the interaction between insulin sensitivity and secretion, the role of adipocytes in the pathogenesis of type 2 diabetes, cellular mechanisms of insulin resistance including glucose transport and phosphorylation, glycogen and synthesis,glucose and oxidation, glycolysis, and insulin signaling.
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Affiliation(s)
- Ralph A DeFronzo
- Diabetes Division, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Abstract
Insulin resistance plays a key role in the pathogenesis of several human diseases, including diabetes, obesity, hypertension, and cardiovascular diseases. The predisposition to insulin resistance results from genetic and environmental factors. The search for gene variants that predispose to insulin resistance has been thwarted by its genetically heterogeneous pathogenesis. However, using techniques of targeted mutagenesis and transgenesis in rodents, investigators have developed mouse models to test critical hypotheses on the pathogenesis of insulin resistance. Moreover, experimental crosses among mutant mice have shed light onto the polygenic nature of the interactions underlying this complex metabolic condition.
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Affiliation(s)
- Anindita Nandi
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, NY, USA
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46
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Abstract
AIM This study was designed to investigate the point prevalence and pattern of obesity in the Jamaican adult population. METHODS A two-stage-stratified random sampling design was used, and individuals aged 15 years and over were interviewed. In addition, anthropometric measurements were performed. The data were analysed using the SPSS statistical software version 8. Non-response was documented and factored into the final analysis of the survey data. RESULTS A total of 2105 individuals responded to the all island survey, with 69% being females. Truncal obesity and gynoid obesity showed similar prevalence data. Both were affected by increasing age, being female, level of education attained and smoking status. CONCLUSIONS Jamaica has a point prevalence of obesity, truncal 36.2% and gynoid 34.1%, in the 15 and over age group.
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Affiliation(s)
- D Ragoobirsingh
- Department of Basic Medical Sciences (Biochemistry Section), University of the West Indies, Kingston, Jamaica, West Indies.
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Abstract
Insulin has multiple metabolic actions, including effects on blood vessels. Insulin normally increases blood flow by a mechanism which involves generation of nitric oxide (NO) via the arginine-NO pathway. Although insulin itself is a weak and physiologically unimportant vasodilatator, it appears to markedly potentiate endothelium-dependent vasodilatation. Therefore, anything that impairs insulin action in endothelial cells can be expected to be associated with endothelial dysfunction, i.e. loss of NO bioactivity in the vessel wall. Consistent with the idea that insulin resistance and endothelial dysfunction frequently coexist, all insulin-resistant conditions examined to date have been associated with endothelial dysfunction. However, the latter can also be caused by factors other than insulin resistance-such as a high concentration of low-density lipoprotein (LDL) cholesterol. Therapies which reverse insulin resistance-such as exercise, insulin and inhibitors of the renin-angiotensin-aldosterone (RAA) axis-also reverse endothelial dysfunction, which may thus be an inherent feature of insulin resistance.
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Affiliation(s)
- Hannele Yki-Järvinen
- Division of Diabetes, Department of Medicine, University of Helsinki, Haartmaninkatu 4, 00290 Helsinki, Finland.
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48
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Abstract
To examine the role of the insulin receptor in fuel homeostasis, we and others have carried out genetic ablation studies in mice. Mice lacking insulin receptors are born with normal features, but develop early postnatal diabetes and die of ketoacidosis. In contrast, mice lacking insulin receptors in specific cell types as a result of conditional mutagenesis develop mild metabolic and reproductive abnormalities. These experiments have uncovered novel functions of insulin receptors in tissues such as brain and pancreatic beta-cells. Combined knockout studies of insulin and Igf1 receptors indicate that the insulin receptor also promotes embryonic growth. Experimental crosses of mice with insulin receptor haploinsufficiency have been instrumental to the genetic analysis of insulin action by enabling us to assign specific roles to different insulin receptor substrates and identify novel elements in insulin signaling.
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Affiliation(s)
- Tadahiro Kitamura
- Naomi Berrie Diabetes Center, Department of Medicine, College of Physicians & Surgeons of Columbia University, New York, New York 10032, USA.
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Affiliation(s)
- Mandeep Bajaj
- Diabetes Division, Department od Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78284-7886, USA.
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Gerich JE. Contributions of insulin-resistance and insulin-secretory defects to the pathogenesis of type 2 diabetes mellitus. Mayo Clin Proc 2003; 78:447-56. [PMID: 12683697 DOI: 10.4065/78.4.447] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Controlled clinical trials have shown that optimal glycemic control can prevent the microvascular complications of type 2 diabetes mellitus; considerable epidemiological data suggest that this may also be true for macrovascular complications. However, this is frequently not achieved. Consequently, research efforts have been undertaken to better understand the pathophysiology of this disorder. It is now well recognized that 2 factors are involved: impaired beta-cell function and insulin resistance. Prospective studies of high-risk populations have shown insulin-resistance and/ or insulin-secretory defects before the onset of impaired glucose tolerance. Thus, there has been a long-standing debate whether an alteration in insulin sensitivity or in insulin secretion is the primary genetic factor. Most of the available evidence favors the view that type 2 diabetes is a heterogeneous disorder in which the major genetic factor is impaired beta-cell function and insulin resistance is the major acquired factor. Superimposition of insulin resistance on a beta cell that cannot appropriately compensate leads to deterioration in glucose tolerance. Therefore, clinicians managing type 2 diabetes must reduce insulin resistance and augment and/or replace beta-cell function.
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Affiliation(s)
- John E Gerich
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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