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Kabir M, Bergman RN, Porter J, Stefanovski D, Paszkiewicz RL, Piccinini F, Woolcott OO, Yang H, Sashi Gopaul V, Stiles L, Kolka CM. Dapagliflozin prevents abdominal visceral and subcutaneous adipose tissue dysfunction in the insulin-resistant canine model. Obesity (Silver Spring) 2023; 31:1798-1811. [PMID: 37221655 PMCID: PMC10981466 DOI: 10.1002/oby.23771] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 05/25/2023]
Abstract
OBJECTIVE Sodium-glucose cotransporter 2 inhibitors (SGLT2i) promote urinary glucose excretion, induce weight loss, and reduce fat accumulation. The effects of the SGLT2i dapagliflozin (DAPA) on subcutaneous (SC) and visceral (VIS) adipose tissue function remain unclear. The objective of this study is to evaluate SC and VIS adipose tissue function in an insulin-resistant canine model. METHODS A total of 12 dogs were fed a high-fat diet (HFD) for 6 weeks and then were given a single low dose of streptozotocin (18.5 mg/kg) to induce insulin resistance. Animals were then randomized and exposed to DAPA (n = 6, 1.25 mg/kg) or placebo (n = 6) once per day for 6 weeks while remaining on the HFD. RESULTS DAPA prevented further weight gain induced by the HFD and normalized fat mass. DAPA reduced fasting glucose and increased free fatty acids, adiponectin, and β-hydroxybutyrate. DAPA reduced adipocyte diameter and cell distribution. Furthermore, DAPA increased genes associated with beiging, lipolysis, and adiponectin secretion and the expression of the adiponectin receptor ADR2, in SC and VIS adipose tissue. DAPA increased AMP-activated protein kinase activity and maximal mitochondrial respiratory function, especially in the SC depot. Furthermore, DAPA reduced cytokines and ceramide synthesis enzymes in SC and VIS depots. CONCLUSIONS For the first time, to our knowledge, we identify mechanisms by which DAPA enhances adipose tissue function in regulating energy homeostasis in an insulin-resistant canine model.
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Affiliation(s)
- Morvarid Kabir
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Richard N Bergman
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Jay Porter
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Darko Stefanovski
- University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA
| | - Rebecca L Paszkiewicz
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Francesca Piccinini
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - Orison O. Woolcott
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
| | - HsiuChiung Yang
- Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca Gothenburg, Sweden
| | - V Sashi Gopaul
- Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca Gothenburg, Sweden
| | - Linsey Stiles
- Department of Endocrinology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - Cathryn M Kolka
- Cedars-Sinai Medical Center, Diabetes and Obesity Research Institute, Los Angeles, California, USA
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Inverse Regulation of Serum Osteoprotegerin and B-Type Natriuretic Peptide Concentrations by Free Fatty Acids Elevation in Young Healthy Humans. Nutrients 2022; 14:nu14040837. [PMID: 35215487 PMCID: PMC8879157 DOI: 10.3390/nu14040837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/06/2022] [Accepted: 02/15/2022] [Indexed: 02/05/2023] Open
Abstract
Osteoprotegerin (OPG) and B-type natriuretic peptide (BNP) are cardiovascular risk factors, interrelated with each other, with possible associations with insulin sensitivity and glucose homeostasis. The aim of this study was to assess association between OPG and BNP concentrations in a young healthy population, their relation to insulin sensitivity and obesity and their regulation by hyperinsulinemia and serum free fatty acids (FFA) elevation. The study group consisted of 59 male volunteers, 30 of whom were of a normal weight (BMI < 25 kg/m2), and 29 were overweight/obese (BMI > 25 kg/m2). Insulin sensitivity was assessed with the 2-h hyperinsulinemic-euglycemic clamp (HEC). In the subgroup of 20 subjects, the clamp was prolonged to 6 h. After one week, another 6-h clamp, with concurrent Intralipid/heparin infusion, was performed. Serum OPG was positively associated with insulin sensitivity (p = 0.002) and negatively with BMI (p = 0.019) and serum BNP (p = 0.025). In response to 6-h hyperinsulinemia, circulating BNP decreased (p < 0.001). In response to HEC with Intralipid/heparin infusion, OPG decreased (p < 0.001) and BNP increased (p < 0.001). Our data show that OPG and BNP are differentially regulated by FFA, which suggests their association with lipid-induced insulin resistance. The assessment of these cardiovascular risk factors should take into account both long-term and short-term effects associated with insulin resistance.
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Chung YL, Rhie YJ. Severe Obesity in Children and Adolescents: Metabolic Effects, Assessment, and Treatment. J Obes Metab Syndr 2021; 30:326-335. [PMID: 34924365 PMCID: PMC8735819 DOI: 10.7570/jomes21063] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 12/23/2022] Open
Abstract
Childhood obesity has been increasing steadily in recent decades, and severe childhood obesity has emerged as a major public health problem both nationally and internationally. A current concern is that lockdown due to the coronavirus disease 2019 (COVID-19) pandemic could exacerbate the spread of childhood obesity and increase the gap in obesity risk. Recent research results indicate the aggravation of obesity after school closures. The consequences of severe childhood obesity are more devastating than those of mild to moderate obesity. Children with severe obesity are at greater risk than others for hypertension, type 2 diabetes, metabolic syndrome, non-alcoholic fatty liver disease, atherosclerosis, and adult obesity. Accurately assessing and diagnosing a child with severe obesity is the key to implementing successful therapy. A detailed and accurate patient history and physical examination are important to discriminate monogenic obesity and metabolic syndrome diagnoses from severe obesity without an underlying cause. Psychosocial factors, including eating behaviors, should be assessed to facilitate better weight management outcomes. Treatment options for severe pediatric obesity include lifestyle modification therapy, pharmacotherapy, and metabolic and bariatric surgery. However, lifestyle modification should be the priority. Although progress has been made, safe and effective treatment for severe pediatric obesity is still challenging. More efforts and innovations are needed to find a solution for the huge medical and emotional burden that these children and their families carry. Public health organizations also need to make efforts to encourage and normalize healthy eating habits and exercise to prevent severe obesity in childhood.
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Affiliation(s)
- Yoojin Lindsey Chung
- Department of Pediatrics, Myongji Hospital, Hanyang University Medical Center, Goyang, Korea
| | - Young-Jun Rhie
- Department of Pediatrics, Korea University Ansan Hospital, Ansan, Korea
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4
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Agaltsov MV, Drapkina OM. Obstructive sleep apnea and cardiovascular comorbidity: common pathophysiological mechanisms to cardiovascular disease. RATIONAL PHARMACOTHERAPY IN CARDIOLOGY 2021. [DOI: 10.20996/1819-6446-2021-08-05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Obstructive sleep apnea (OSA) is associated with many cardiovascular and metabolic diseases. Sleep apnea causes intermittent hypoxemia, chest pressure fluctuations and a reaction from the cerebral cortex in the form of a short awakening during sleep (EEG-activation). The consequences of pathological pathways are studied in experimental models involving cell cultures, animals, and healthy volunteers. At present, the negative impact of intermittent hypoxemia on a variety of pathophysiological disorders of the heart and blood vessels (vascular tone fluctuations, thickening of the intimamedia complex in the vascular wall, direct damaging effect on the myocardium) has a great evidence base. Two other pathological components of OSA (pressure fluctuations and EEG-activation) can also affect cardiovascular system, mainly affecting the increase in blood pressure and changing cardiac hemodynamics. Although these reactions are considered separately in the review, with the development of sleep apnea they occur sequentially and are closely interrelated. As a result, these pathological pathways trigger further pathophysiological mechanisms acting on the heart and blood vessels. It is known that these include excessive sympathetic activation, inflammation, oxidative stress and metabolic dysregulation. In many respects being links of one process, these mechanisms can trigger damage to the vascular wall, contributing to the formation of atherosclerotic lesions. The accumulated data with varying degrees of reliability confirm the participation of OSA through these processes in the formation of cardiovascular disorders. There are factors limiting direct evidence of this interaction (sleep deprivation, causing similar changes, as well as the inability to share the contribution of other risk factors for cardiovascular diseases, in particular arterial hypertension, obesity, which are often associated with OSA). It is necessary to continue the study of processes that implement the pathological effect of OSA on the cardiovascular system.
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Affiliation(s)
- M. V. Agaltsov
- National Medical Research Center for Therapy and Preventive Medicine
| | - O. M. Drapkina
- National Medical Research Center for Therapy and Preventive Medicine
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5
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Ader M, Bergman RN. Hyperinsulinemic Compensation for Insulin Resistance Occurs Independent of Elevated Glycemia in Male Dogs. Endocrinology 2021; 162:6300300. [PMID: 34132779 PMCID: PMC8282122 DOI: 10.1210/endocr/bqab119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Indexed: 11/19/2022]
Abstract
Insulin resistance engenders a compensatory increase in plasma insulin. Inadequate compensation is a primary element in the pathogenesis of type 2 diabetes. The signal that heralds developing insulin resistance and initiates hyperinsulinemic compensation is not known. It has often been assumed to be increased glucose. We tested this assumption by determining whether development of fasting and/or glucose-stimulated hyperinsulinemia with diet-induced insulin resistance occurs because of concomitant elevation of glycemia. Male dogs (n = 58) were fed a hypercaloric, fat-supplemented diet for 6 weeks. Dogs underwent magnetic resonance imaging to quantify total and regional (visceral, subcutaneous) adiposity as well as euglycemic hyperinsulinemic clamps. A subset of animals also underwent an insulin-modified intravenous glucose tolerance test to assess insulin sensitivity, acute insulin response (AIRg), and glucose effectiveness. Fat feeding caused modest weight gain, increased visceral and subcutaneous fat, and insulin resistance at both peripheral and hepatic levels. Hyperinsulinemic compensation was observed in fasting levels as well as increased AIRg. However, we observed absolutely no increase in carefully measured fasting, evening (6 to 8 pm) or nocturnal glycemia (2 to 4 am). Insulin resistance and hyperinsulinemia occurred despite no elevation in 24-hour glucose. Compensatory development of hyperinsulinemia during diet-induced insulin resistance occurs without elevated fasting or 24-hour glycemia. These data refute the idea that glucose itself is a requisite signal for β-cell upregulation. Alternative feedback mechanisms need to be identified.
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Affiliation(s)
- Marilyn Ader
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Correspondence: Marilyn Ader, Ph.D., Associate Director, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 116 N. Robertson Blvd, PACT 700.8V, Los Angeles, CA 90048, United States. E-mail:
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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6
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Stefanovski D, Punjabi NM, Boston RC, Watanabe RM. Insulin Action, Glucose Homeostasis and Free Fatty Acid Metabolism: Insights From a Novel Model. Front Endocrinol (Lausanne) 2021; 12:625701. [PMID: 33815283 PMCID: PMC8010655 DOI: 10.3389/fendo.2021.625701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/01/2021] [Indexed: 12/05/2022] Open
Abstract
Glucose and free fatty acids (FFA) are essential nutrients that are both partly regulated by insulin. Impaired insulin secretion and insulin resistance are hallmarks of aberrant glucose disposal, and type 2 diabetes (T2DM). In the current study, a novel model of FFA kinetics is proposed to estimate the role insulin action on FFA lipolysis and oxidation allowing estimation of adipose tissue insulin sensitivity (SIFFA ). Twenty-five normal volunteers were recruited for the current study. To participate, volunteers had to be less than 40 years of age and have a body mass index (BMI) < 30 kg/m2, and be free of medical comorbidity. The proposed model of FFA kinetics was used to analyze the data derived from the insulin-modified FSIGT. Mean fractional standard deviations of the parameter estimates were all less than 20%. Standardized residuals of the fit of the model to the FFA temporal data were randomly distributed, with only one estimated point lying outside the 2-standard deviation range, suggesting an acceptable fit of the model to the FFA data. The current study describes a novel one-compartment non-linear model of FFA kinetics during an FSIGT that provides an FFA metabolism insulin sensitivity parameter (SIFFA ). Furthermore, the models suggest a new role of glucose as the modulator of FFA disposal. Estimates of SIFFA confirmed previous findings that FFA metabolism is more sensitive to changes in insulin than glucose metabolism. Novel derived indices of insulin sensitivity of FFA (SIFFA ) were correlated with minimal model indices. These associations suggest a cooperative rather than competitive interplay between the two primary nutrients (glucose and FFA) and allude to the FFA acting as the buffer, such that glucose homeostasis is maintained.
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Affiliation(s)
- Darko Stefanovski
- School of Veterinary Medicine, University of Pennsylvania, New Bolton Center, PA, United States
- *Correspondence: Darko Stefanovski,
| | - Naresh M. Punjabi
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Raymond C. Boston
- School of Veterinary Medicine, University of Pennsylvania, New Bolton Center, PA, United States
| | - Richard M. Watanabe
- Department of Preventive Medicine, Keck School of Medicine of USC, Los Angeles, CA, United States
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7
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Brouwer A, Asare Bediako I, Paszkiewicz RL, Kolka CM, Bergman RN, Broussard JL. Impact of sleep deprivation and high-fat feeding on insulin sensitivity and beta cell function in dogs. Diabetologia 2020; 63:875-884. [PMID: 32016566 PMCID: PMC7304935 DOI: 10.1007/s00125-019-05084-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/06/2019] [Indexed: 12/15/2022]
Abstract
AIMS/HYPOTHESIS Insufficient sleep is increasingly recognised as a major risk factor for the development of obesity and diabetes, and short-term sleep loss in clinical studies leads to a reduction in insulin sensitivity. Sleep loss-induced metabolic impairments are clinically relevant, since reductions in insulin sensitivity after sleep loss are comparable to insulin sensitivity differences between healthy individuals and those with impaired glucose tolerance. However, the relative effects of sleep loss vs high-fat feeding in the same individual have not been assessed. In addition, to our knowledge no diurnal (active during the daytime) non-human mammalian model of sleep loss-induced metabolic impairment exists, which limits our ability to study links between sleep and metabolism. METHODS This study examined the effects of one night of total sleep deprivation on insulin sensitivity and beta cell function, as assessed by an IVGTT, before and after 9 months of high-fat feeding in a canine model. RESULTS One night of total sleep deprivation in lean dogs impaired insulin sensitivity to a similar degree as a chronic high-fat diet (HFD)(normal sleep: 4.95 ± 0.45 mU-1 l-1 min-1; sleep deprivation: 3.14 ± 0.21 mU-1 l-1 min-1; HFD: 3.74 ± 0.48 mU-1 l-1 min-1; mean ± SEM). Hyperinsulinaemic compensation was induced by the chronic HFD, suggesting adequate beta cell response to high-fat feeding. In contrast, there was no beta cell compensation after one night of sleep deprivation, suggesting that there was metabolic dysregulation with acute sleep loss that, if sustained during chronic sleep loss, could contribute to the risk of type 2 diabetes. After chronic high-fat feeding, acute total sleep deprivation did not cause further impairments in insulin sensitivity (sleep deprivation + chronic HFD: 3.28 mU-1 l-1 min-1). CONCLUSIONS/INTERPRETATION Our findings provide further evidence that sleep is important for metabolic health and establish a diurnal animal model of metabolic disruption during insufficient sleep.
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Affiliation(s)
- Annelies Brouwer
- Sleep and Metabolism Laboratory, Department of Health and Exercise Science, Colorado State University, 1582 Campus Delivery, Fort Collins, CO, 80523-1582, USA
- Amsterdam UMC, Vrije Universiteit, Department of Psychiatry, Amsterdam Public Health Research Institute, Amsterdam, the Netherlands
- GGZ inGeest Specialized Mental Health Care, Amsterdam, the Netherlands
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Josiane L Broussard
- Sleep and Metabolism Laboratory, Department of Health and Exercise Science, Colorado State University, 1582 Campus Delivery, Fort Collins, CO, 80523-1582, USA.
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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8
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Kolka CM. The vascular endothelium plays a role in insulin action. Clin Exp Pharmacol Physiol 2019; 47:168-175. [PMID: 31479553 DOI: 10.1111/1440-1681.13171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/23/2019] [Accepted: 08/27/2019] [Indexed: 12/30/2022]
Abstract
The endocrine system relies on the vasculature for delivery of hormones throughout the body, and the capillary microvasculature is the site where the hormones cross from the blood into the target tissue. Once considered an inert wall, various studies have now highlighted the functions of the capillary endothelium to regulate transport and therefore affect or maintain the interstitial environment. The role of the capillary may be clear in areas where there is a continuous endothelium, yet there also appears to be a role of endothelial cells in tissues with a sinusoidal structure. Here we focused on the most common endocrine disorder, diabetes, and several of the target organs associated with the disease, including skeletal muscle, liver and pancreas. However, it is important to note that the ability of hormones to cross the endothelium to reach their target tissue is a component of all endocrine functions. It is also a consideration in organs throughout the body and may have greater impact for larger hormones with target tissues containing a continuous endothelium. We noted that the blood levels do not always equal interstitial levels, which is what the cells are exposed to, and discussed how this may change in diseases such as obesity and insulin resistance. The capillary endothelium is, therefore, an essential and understudied aspect of endocrinology and metabolism that can be altered in disease, which may be an appropriate target for treatment.
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Affiliation(s)
- Cathryn M Kolka
- Department of Biomedical Science, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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9
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Iyer MS, Paszkiewicz RL, Bergman RN, Richey JM, Woolcott OO, Asare-Bediako I, Wu Q, Kim SP, Stefanovski D, Kolka CM, Clegg DJ, Kabir M. Activation of NPRs and UCP1-independent pathway following CB1R antagonist treatment is associated with adipose tissue beiging in fat-fed male dogs. Am J Physiol Endocrinol Metab 2019; 317:E535-E547. [PMID: 31237449 PMCID: PMC6766608 DOI: 10.1152/ajpendo.00539.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 06/21/2019] [Accepted: 06/24/2019] [Indexed: 11/22/2022]
Abstract
CB1 receptor (CB1R) antagonism improves the deleterious effects of a high-fat diet (HFD) by reducing body fat mass and adipocyte cell size. Previous studies demonstrated that the beneficial effects of the CB1R antagonist rimonabant (RIM) in white adipose tissue (WAT) are partially due to an increase of mitochondria numbers and upregulation thermogenesis markers, suggesting an induction of WAT beiging. However, the molecular mechanism by which CB1R antagonism induces weight loss and WAT beiging is unclear. In this study, we probed for genes associated with beiging and explored longitudinal molecular mechanisms by which the beiging process occurs. HFD dogs received either RIM (HFD+RIM) or placebo (PL) (HFD+PL) for 16 wk. Several genes involved in beiging were increased in HFD+RIM compared with pre-fat, HFD, and HFD+PL. We evaluated lipolysis and its regulators including natriuretic peptide (NP) and its receptors (NPRs), β-1 and β-3 adrenergic receptor (β1R, β3R) genes. These genes were increased in WAT depots, accompanied by an increase in lipolysis in HFD+RIM. In addition, RIM decreased markers of inflammation and increased adiponectin receptors in WAT. We observed a small but significant increase in UCP1; therefore, we evaluated the newly discovered UCP1-independent thermogenesis pathway. We confirmed that SERCA2b and RYR2, the two key genes involved in this pathway, were upregulated in the WAT. Our data suggest that the upregulation of NPRs, β-1R and β-3R, lipolysis, and SERCA2b and RYR2 may be one of the mechanisms by which RIM promotes beiging and overall the improvement of metabolic homeostasis induced by RIM.
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MESH Headings
- Adipose Tissue/drug effects
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, White/drug effects
- Animals
- Diet, High-Fat/adverse effects
- Dogs
- Gene Expression/drug effects
- Inflammation/pathology
- Inflammation/prevention & control
- Insulin Resistance
- Male
- Organelle Biogenesis
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Receptors, Atrial Natriuretic Factor/drug effects
- Rimonabant/pharmacology
- Thermogenesis/drug effects
- Thermogenesis/genetics
- Uncoupling Protein 1/drug effects
- Weight Loss/drug effects
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Affiliation(s)
- Malini S Iyer
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | | | - Richard N Bergman
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Joyce M Richey
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Orison O Woolcott
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Isaac Asare-Bediako
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Qiang Wu
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Stella P Kim
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Darko Stefanovski
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Cathryn M Kolka
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Deborah J Clegg
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
| | - Morvarid Kabir
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California
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10
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Thomas DD, Corkey BE, Istfan NW, Apovian CM. Hyperinsulinemia: An Early Indicator of Metabolic Dysfunction. J Endocr Soc 2019; 3:1727-1747. [PMID: 31528832 PMCID: PMC6735759 DOI: 10.1210/js.2019-00065] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/18/2019] [Indexed: 02/06/2023] Open
Abstract
Hyperinsulinemia is strongly associated with type 2 diabetes. Racial and ethnic minority populations are disproportionately affected by diabetes and obesity-related complications. This mini-review provides an overview of the genetic and environmental factors associated with hyperinsulinemia with a focus on racial and ethnic differences and its metabolic consequences. The data used in this narrative review were collected through research in PubMed and reference review of relevant retrieved articles. Insulin secretion and clearance are regulated processes that influence the development and progression of hyperinsulinemia. Environmental, genetic, and dietary factors are associated with hyperinsulinemia. Certain pharmacotherapies for obesity and bariatric surgery are effective at mitigating hyperinsulinemia and are associated with improved metabolic health. Hyperinsulinemia is associated with many environmental and genetic factors that interact with a wide network of hormones. Recent studies have advanced our understanding of the factors affecting insulin secretion and clearance. Further basic and translational work on hyperinsulinemia may allow for earlier and more personalized treatments for obesity and metabolic diseases.
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Affiliation(s)
- Dylan D Thomas
- Department of Medicine, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
| | - Barbara E Corkey
- Department of Medicine, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
| | - Nawfal W Istfan
- Department of Medicine, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
| | - Caroline M Apovian
- Department of Medicine, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
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Rynders CA, Pereira RI, Bergouignan A, Kealey EH, Bessesen DH. Associations Among Dietary Fat Oxidation Responses to Overfeeding and Weight Gain in Obesity-Prone and Resistant Adults. Obesity (Silver Spring) 2018; 26:1758-1766. [PMID: 30358145 PMCID: PMC6214358 DOI: 10.1002/oby.22321] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/30/2018] [Accepted: 08/30/2018] [Indexed: 12/20/2022]
Abstract
OBJECTIVE This study tested the hypothesis that 3 days of overfeeding (OF) decreases dietary fat oxidation and predicts longitudinal weight change in adults classified as obesity prone (OP) and obesity resistant (OR) based on self-identification and personal and family weight history. Changes in diurnal profiles of plasma metabolites and hormones were measured to probe mechanisms. METHODS Adults identified as OP (n = 22; BMI: 23.9 ± 2.4 kg/m2 ) and OR (n = 30; BMI: 20.5 ± 2.2 kg/m2 ) completed 3 days of eucaloric (EU) feeding and 3 days of OF. On day 3, the 24-hour total and dietary fat oxidation was measured using room calorimetry and an oral 14 C tracer. Plasma glucose, insulin, triglycerides, and nonesterified fatty acid (NEFA) concentrations were frequently sampled over 24 hours. Body composition was measured annually for 4.0 ± 1.4 years in a subsample (n = 19 OP and 23 OR). RESULTS Dietary fat oxidation over 24 hours was not altered by OF versus EU (P = 0.54). Weight gain in OP correlated with lower nocturnal NEFA concentrations during OF (r = -0.60; P = 0.006) and impaired fuel selection over 24 hours (metabolic inflexibility, wake respiratory quotient-sleep respiratory quotient) (r = -0.48; P = 0.04). CONCLUSIONS Short-term OF did not alter dietary fat oxidation. Lower nocturnal NEFA availability and metabolic inflexibility to overfeeding may be factors contributing to weight gain.
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Affiliation(s)
- Corey A. Rynders
- Division of Geriatric Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Rocio I. Pereira
- Denver Health Medical Center, Division of Endocrinology, Denver, Colorado, USA
| | - Audrey Bergouignan
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
- Anschutz Health & Wellness Center at the University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
- IPHC-DEPE, Université de Strasbourg, Strasbourg, France
- UMR 7178 Centre National de la Recherche scientifique (CNRS), Strasbourg, France
| | - Elizabeth H. Kealey
- Anschutz Health & Wellness Center at the University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Daniel H. Bessesen
- Denver Health Medical Center, Division of Endocrinology, Denver, Colorado, USA
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
- Anschutz Health & Wellness Center at the University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
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12
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Haeusler RA, McGraw TE, Accili D. Biochemical and cellular properties of insulin receptor signalling. Nat Rev Mol Cell Biol 2018; 19:31-44. [PMID: 28974775 PMCID: PMC5894887 DOI: 10.1038/nrm.2017.89] [Citation(s) in RCA: 409] [Impact Index Per Article: 68.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The mechanism of insulin action is a central theme in biology and medicine. In addition to the rather rare condition of insulin deficiency caused by autoimmune destruction of pancreatic β-cells, genetic and acquired abnormalities of insulin action underlie the far more common conditions of type 2 diabetes, obesity and insulin resistance. The latter predisposes to diseases ranging from hypertension to Alzheimer disease and cancer. Hence, understanding the biochemical and cellular properties of insulin receptor signalling is arguably a priority in biomedical research. In the past decade, major progress has led to the delineation of mechanisms of glucose transport, lipid synthesis, storage and mobilization. In addition to direct effects of insulin on signalling kinases and metabolic enzymes, the discovery of mechanisms of insulin-regulated gene transcription has led to a reassessment of the general principles of insulin action. These advances will accelerate the discovery of new treatment modalities for diabetes.
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Affiliation(s)
- Rebecca A Haeusler
- Columbia University College of Physicians and Surgeons, Department of Pathology and Cell Biology, New York, New York 10032, USA
| | - Timothy E McGraw
- Weill Cornell Medicine, Departments of Biochemistry and Cardiothoracic Surgery, New York, New York 10065, USA
| | - Domenico Accili
- Columbia University College of Physicians & Surgeons, Department of Medicine, New York, New York 10032, USA
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13
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Broussard JL, Bergman RN, Bediako IA, Paszkiewicz RL, Iyer MS, Kolka CM. Insulin Access to Skeletal Muscle is Preserved in Obesity Induced by Polyunsaturated Diet. Obesity (Silver Spring) 2018; 26:119-125. [PMID: 29193779 PMCID: PMC5739979 DOI: 10.1002/oby.22057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/27/2017] [Accepted: 09/28/2017] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Diets high in saturated fat induce obesity and insulin resistance and impair insulin access to skeletal muscle, leading to reduced insulin levels at the muscle cell surface available to bind insulin receptors and induce glucose uptake. In contrast, diets supplemented with polyunsaturated fat improve insulin sensitivity (SI) and reduce the risk for type 2 diabetes. It was hypothesized that a diet high in polyunsaturated fat would preserve SI and insulin access to muscle, as compared with a diet high in saturated fat. METHODS After 12 weeks of control, saturated (LARD), or polyunsaturated (salmon oil [SO]) high-fat diet feeding, muscle SI and insulin access to skeletal muscle were measured by using lymph, a surrogate of skeletal muscle interstitial fluid. RESULTS Both high-fat diets induced similar weight gain, yet only LARD impaired SI. Hyperinsulinemia in the LARD group did not induce an increase in basal interstitial insulin, suggesting reduced insulin access to muscle after LARD, but not after SO. CONCLUSIONS A diet high in polyunsaturated fat does not impair insulin access to muscle interstitium or induce insulin resistance as observed with a saturated fat diet, despite similar weight gain. Future studies should determine whether dietary SO supplementation improves impairments in insulin access to skeletal muscle.
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Affiliation(s)
- Josiane L Broussard
- Department of Integrated Physiology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Department of Biomedical Science, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Department of Biomedical Science, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Department of Biomedical Science, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Malini S Iyer
- Diabetes and Obesity Research Institute, Department of Biomedical Science, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Department of Biomedical Science, Cedars-Sinai Medical Center, Los Angeles, California, USA
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14
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Chopra S, Rathore A, Younas H, Pham LV, Gu C, Beselman A, Kim IY, Wolfe RR, Perin J, Polotsky VY, Jun JC. Obstructive Sleep Apnea Dynamically Increases Nocturnal Plasma Free Fatty Acids, Glucose, and Cortisol During Sleep. J Clin Endocrinol Metab 2017; 102:3172-3181. [PMID: 28595341 PMCID: PMC5587067 DOI: 10.1210/jc.2017-00619] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/12/2017] [Indexed: 11/19/2022]
Abstract
CONTEXT Obstructive sleep apnea (OSA) is associated with diabetes and cardiovascular disease. This association may be related to metabolic changes that transpire during sleep in OSA. OBJECTIVE To examine the impact of OSA, elicited by cessation of continuous positive airway pressure (CPAP), on frequently sampled nocturnal metabolic markers including plasma free fatty acids (FFAs), glucose, insulin, triglycerides (TGs), cortisol, and lactate, as well as glucose production, oral glucose tolerance, blood pressure (BP), endothelial function, cholesterol, and high-sensitivity C-reactive protein (hsCRP). DESIGN AND SETTING Randomized crossover trial of CPAP vs CPAP withdrawal. PATIENTS Thirty-one patients with moderate to severe OSA acclimated to CPAP. INTERVENTION Patients underwent attended polysomnography while sleeping with therapeutic CPAP, or after CPAP withdrawal, in random order. Venous blood was sampled at ∼20-minute intervals on both nights. In 11 patients, we assessed glucose kinetics with an infusion of 6,6-[2H2]glucose. RESULTS CPAP withdrawal caused recurrence of OSA associated with hypoxemia, sleep disruption, and heart rate (HR) elevation. CPAP withdrawal dynamically increased nocturnal FFA (P = 0.007), glucose (P = 0.028), and cortisol (P = 0.037), in proportion to respiratory event frequency, HR elevation, or sleep fragmentation. Diabetes predisposed to glucose elevation. CPAP withdrawal also increased systolic BP (P = 0.017) and augmentation index (P = 0.008), but did not affect insulin, TGs, glucose production, oral glucose tolerance, cholesterol, or hsCRP. CONCLUSION OSA recurrence during CPAP withdrawal increases FFA and glucose during sleep, associated with sympathetic and adrenocortical activation. Recurring exposure to these metabolic changes may foster diabetes and cardiovascular disease.
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Affiliation(s)
- Swati Chopra
- Division of Pulmonary and Critical Care, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224
| | - Aman Rathore
- Division of Pulmonary and Critical Care, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224
| | - Haris Younas
- Division of Pulmonary and Critical Care, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224
| | - Luu V. Pham
- Division of Pulmonary and Critical Care, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224
| | - Chenjuan Gu
- Department of Respiratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Aleksandra Beselman
- Department of Pharmacy Services, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224
| | - Il-Young Kim
- Center for Translational Research in Aging & Longevity, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Robert R. Wolfe
- Center for Translational Research in Aging & Longevity, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Jamie Perin
- School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205
| | - Vsevolod Y. Polotsky
- Division of Pulmonary and Critical Care, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224
| | - Jonathan C. Jun
- Division of Pulmonary and Critical Care, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224
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15
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Morton GJ, Muta K, Kaiyala KJ, Rojas JM, Scarlett JM, Matsen ME, Nelson JT, Acharya NK, Piccinini F, Stefanovski D, Bergman RN, Taborsky GJ, Kahn SE, Schwartz MW. Evidence That the Sympathetic Nervous System Elicits Rapid, Coordinated, and Reciprocal Adjustments of Insulin Secretion and Insulin Sensitivity During Cold Exposure. Diabetes 2017; 66:823-834. [PMID: 28115396 PMCID: PMC5360298 DOI: 10.2337/db16-1351] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 01/03/2017] [Indexed: 12/21/2022]
Abstract
Dynamic adjustment of insulin secretion to compensate for changes of insulin sensitivity that result from alteration of nutritional or metabolic status is a fundamental aspect of glucose homeostasis. To investigate the role of the brain in this coupling process, we used cold exposure as an experimental paradigm because the sympathetic nervous system (SNS) helps to coordinate the major shifts of tissue glucose utilization needed to ensure that increased thermogenic needs are met. We found that glucose-induced insulin secretion declined by 50% in rats housed at 5°C for 28 h, and yet, glucose tolerance did not change, owing to a doubling of insulin sensitivity. These potent effects on insulin secretion and sensitivity were fully reversed by returning animals to room temperature (22°C) for 4 h or by intravenous infusion of the α-adrenergic receptor antagonist phentolamine for only 30 min. By comparison, insulin clearance was not affected by cold exposure or phentolamine infusion. These findings offer direct evidence of a key role for the brain, acting via the SNS, in the rapid, highly coordinated, and reciprocal changes of insulin secretion and insulin sensitivity that preserve glucose homeostasis in the setting of cold exposure.
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Affiliation(s)
- Gregory J Morton
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Kenjiro Muta
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Karl J Kaiyala
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA
| | - Jennifer M Rojas
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Jarrad M Scarlett
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
- Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA
| | - Miles E Matsen
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Jarrell T Nelson
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Nikhil K Acharya
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Francesca Piccinini
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Darko Stefanovski
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Gerald J Taborsky
- Veterans Affairs Puget Sound Health Care System, Department of Veterans Affairs Medical Center, Seattle, WA
| | - Steven E Kahn
- Veterans Affairs Puget Sound Health Care System, Department of Veterans Affairs Medical Center, Seattle, WA
| | - Michael W Schwartz
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
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16
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Kim MK, Reaven GM, Kim SH. Dissecting the relationship between obesity and hyperinsulinemia: Role of insulin secretion and insulin clearance. Obesity (Silver Spring) 2017; 25:378-383. [PMID: 28000428 PMCID: PMC5269435 DOI: 10.1002/oby.21699] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/26/2016] [Accepted: 09/12/2016] [Indexed: 01/31/2023]
Abstract
OBJECTIVE The aim of this study was to better delineate the complex interrelationship among insulin resistance (IR), secretion rate (ISR), and clearance rate (ICR) to increase plasma insulin concentrations in obesity. METHODS Healthy volunteers (92 nondiabetic individuals) had an insulin suppression test to measure IR and graded-glucose infusion test to measure ISR and ICR. Obesity was defined as a body mass index (BMI) ≥30 kg/m2 , and IR was defined as steady-state plasma glucose (SSPG) ≥10 mmol/L during the insulin suppression test. Plasma glucose and insulin concentrations, ISR, and ICR were compared in three groups: insulin sensitive/overweight; insulin sensitive/obesity; and insulin resistant/obesity. RESULTS Compared with the insulin-sensitive/overweight group, the insulin-sensitive/obesity had significantly higher insulin area under the curve (AUC) and ISR AUC during the graded-glucose infusion test (P < 0.001). Glucose AUC and ICR were similar. The insulin-resistant/obesity group had higher insulin AUC and ISR AUC compared with the insulin-sensitive/obesity but also had higher glucose AUC and decreased ICR (P < 0.01). In multivariate analysis, both BMI and SSPG were significantly associated with ISR. CONCLUSIONS Plasma insulin concentration and ISR are increased in individuals with obesity, irrespective of degree of IR, but a decrease in ICR is confined to the subset of individuals with IR.
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Affiliation(s)
- Mee Kyoung Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | - Gerald M. Reaven
- Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Sun H. Kim
- Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
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17
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Zhan S, Wu Y, Sun P, Lin H, Zhu Y, Han X. Decrease in Circulating Fatty Acids Is Associated with Islet Dysfunction in Chronically Sleep-Restricted Rats. Int J Mol Sci 2016; 17:ijms17122102. [PMID: 27983645 PMCID: PMC5187902 DOI: 10.3390/ijms17122102] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 12/06/2016] [Accepted: 12/10/2016] [Indexed: 01/04/2023] Open
Abstract
Previous studies have shown that sleep restriction-induced environmental stress is associated with abnormal metabolism, but the underlying mechanism is poorly understood. In the current study, we investigated the possible lipid and glucose metabolism patterns in chronically sleep-restricted rat. Without changes in food intake, body weight was decreased and energy expenditure was increased in sleep-restricted rats. The effects of chronic sleep disturbance on metabolites in serum were examined using 1H NMR metabolomics and GC-FID/MS analysis. Six metabolites (lipoproteins, triglycerides, isoleucine, valine, choline, and phosphorylcholine) exhibited significant alteration, and all the fatty acid components were decreased, which suggested fatty acid metabolism was impaired after sleep loss. Moreover, increased blood glucose, reduced serum insulin, decreased glucose tolerance, and impaired glucose-stimulated insulin secretion of islets were also observed in sleep-restricted rats. The islet function of insulin secretion could be partially restored by increasing dietary fat to sleep-disturbed rats suggested that a reduction in circulating fatty acids was related to islet dysfunction under sleep deficiency-induced environmental stress. This study provides a new perspective on the relationship between insufficient sleep and lipid/glucose metabolism, which offers insights into the role of stressful challenges in a healthy lifestyle.
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Affiliation(s)
- Shanshan Zhan
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Jiangsu Diabetes Center, Nanjing Medical University, Nanjing 210029, China.
| | - Yangyang Wu
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Jiangsu Diabetes Center, Nanjing Medical University, Nanjing 210029, China.
| | - Peng Sun
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Jiangsu Diabetes Center, Nanjing Medical University, Nanjing 210029, China.
| | - Haiyan Lin
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Jiangsu Diabetes Center, Nanjing Medical University, Nanjing 210029, China.
| | - Yunxia Zhu
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Jiangsu Diabetes Center, Nanjing Medical University, Nanjing 210029, China.
| | - Xiao Han
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Jiangsu Diabetes Center, Nanjing Medical University, Nanjing 210029, China.
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18
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Iyer MS, Bergman RN, Korman JE, Woolcott OO, Kabir M, Victor RG, Clegg DJ, Kolka C. Renal Denervation Reverses Hepatic Insulin Resistance Induced by High-Fat Diet. Diabetes 2016; 65:3453-3463. [PMID: 27495220 PMCID: PMC5079632 DOI: 10.2337/db16-0698] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/26/2016] [Indexed: 12/18/2022]
Abstract
Activation of the sympathetic nervous system (SNS) constitutes a putative mechanism of obesity-induced insulin resistance. Thus, we hypothesized that inhibiting the SNS by using renal denervation (RDN) will improve insulin sensitivity (SI) in a nonhypertensive obese canine model. SI was measured using euglycemic-hyperinsulinemic clamp (EGC), before (week 0 [w0]) and after 6 weeks of high-fat diet (w6-HFD) feeding and after either RDN (HFD + RDN) or sham surgery (HFD + sham). As expected, HFD induced insulin resistance in the liver (sham 2.5 ± 0.6 vs. 0.7 ± 0.6 × 10-4 dL ⋅ kg-1 ⋅ min-1 ⋅ pmol/L-1 at w0 vs. w6-HFD [P < 0.05], respectively; HFD + RDN 1.6 ± 0.3 vs. 0.5 ± 0.3 × 10-4 dL ⋅ kg-1 ⋅ min-1 ⋅ pmol/L-1 at w0 vs. w6-HFD [P < 0.001], respectively). In sham animals, this insulin resistance persisted, yet RDN completely normalized hepatic SI in HFD-fed animals (1.8 ± 0.3 × 10-4 dL ⋅ kg-1 ⋅ min-1 ⋅ pmol/L-1 at HFD + RDN [P < 0.001] vs. w6-HFD, [P not significant] vs. w0) by reducing hepatic gluconeogenic genes, including G6Pase, PEPCK, and FOXO1. The data suggest that RDN downregulated hepatic gluconeogenesis primarily by upregulating liver X receptor α through the natriuretic peptide pathway. In conclusion, bilateral RDN completely normalizes hepatic SI in obese canines. These preclinical data implicate a novel mechanistic role for the renal nerves in the regulation of insulin action specifically at the level of the liver and show that the renal nerves constitute a new therapeutic target to counteract insulin resistance.
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Affiliation(s)
- Malini S Iyer
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Jeremy E Korman
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Orison O Woolcott
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Morvarid Kabir
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Ronald G Victor
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Deborah J Clegg
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Cathryn Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
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19
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Broussard JL, Castro AVB, Iyer M, Paszkiewicz RL, Bediako IA, Szczepaniak LS, Szczepaniak EW, Bergman RN, Kolka CM. Insulin access to skeletal muscle is impaired during the early stages of diet-induced obesity. Obesity (Silver Spring) 2016; 24:1922-8. [PMID: 27569119 PMCID: PMC5004780 DOI: 10.1002/oby.21562] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/06/2016] [Accepted: 04/28/2016] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Insulin must move from the blood to the interstitium to initiate signaling, yet access to the interstitium may be impaired in cases of insulin resistance, such as obesity. This study investigated whether consuming a short- and long-term high-fat diet (HFD) impairs insulin access to skeletal muscle, the major site of insulin-mediated glucose uptake. METHODS Male mongrel dogs were divided into three groups consisting of control diet (n = 16), short-term (n = 8), and long-term HFD (n = 8). Insulin sensitivity was measured with intravenous glucose tolerance tests. A hyperinsulinemic euglycemic clamp was performed in each animal at the conclusion of the study. During the clamp, lymph fluid was measured as a representation of the interstitial space to assess insulin access to muscle. RESULTS Short- and long-term HFD induced obesity and reduced insulin sensitivity. Lymph insulin concentrations were approximately 50% of plasma insulin concentrations under control conditions. Long-term HFD caused fasting plasma hyperinsulinemia; however, interstitial insulin concentrations were not increased, suggesting impaired insulin access to muscle. CONCLUSIONS A HFD rapidly induces insulin resistance at the muscle and impairs insulin access under basal insulin concentrations. Hyperinsulinemia induced by a long-term HFD may be a compensatory mechanism necessary to maintain healthy insulin levels in muscle interstitium.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ana V B Castro
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Malini Iyer
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | | | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
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20
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Okada AK, Teranishi K, Isas JM, Bedrood S, Chow RH, Langen R. Diabetic Risk Factors Promote Islet Amyloid Polypeptide Misfolding by a Common, Membrane-mediated Mechanism. Sci Rep 2016; 6:31094. [PMID: 27531121 PMCID: PMC4987648 DOI: 10.1038/srep31094] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/14/2016] [Indexed: 12/14/2022] Open
Abstract
The current diabetes epidemic is associated with a diverse set of risk factors including obesity and exposure to plastics. Notably, significant elevations of negatively charged amphiphilic molecules are observed in obesity (e.g. free fatty acids and phosphatidic acid) and plastics exposure (monophthalate esters). It remains unclear whether these factors share pathogenic mechanisms and whether links exist with islet amyloid polypeptide (IAPP) misfolding, a process central to β-cell dysfunction and death. Using a combination of fluorescence, circular dichroism and electron microscopy, we show that phosphatidic acid, oleic acid, and the phthalate metabolite MBzP partition into neutral membranes and enhance IAPP misfolding. The elevation of negative charge density caused by the presence of the risk factor molecules stabilizes a common membrane-bound α-helical intermediate that, in turn, facilitates IAPP misfolding. This shared mechanism points to a critical role for the membrane-bound intermediate in disease pathogenesis, making it a potential target for therapeutic intervention.
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Affiliation(s)
- Alan K Okada
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - Kazuki Teranishi
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - J Mario Isas
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - Sahar Bedrood
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Robert H Chow
- Department of Physiology and Biophysics, Keck School of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - Ralf Langen
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
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21
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Chen W, Li XM, Li AL, Yang G, Hu HN. Hepatitis C Virus Increases Free Fatty Acids Absorption and Promotes its Replication Via Down-Regulating GADD45α Expression. Med Sci Monit 2016; 22:2347-56. [PMID: 27381636 PMCID: PMC4946386 DOI: 10.12659/msm.899591] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Hepatitis C virus (HCV) infection, as a major cause of chronic hepatic diseases, is always accompanied with an abnormality of lipid metabolism. The aim of this study was to investigate the pathogenic role of free fatty acids (FFA) in human HCV infection. MATERIAL AND METHODS Peripheral blood lipid indexes among HCV patients with different viral loads (199 samples) and healthy donors (80 samples) were detected by clinical biochemistry tests. HCV replication and the expression of growth arrest and DNA-damage-inducible gene 45-α (GADD45α) in Huh7 cells and clinical samples were quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Lipid accumulation in Huh7 cells was detected by immunofluorescence. RESULTS In this study, we found that FFA showed a significant positive correlation with viral load in peripheral blood of HCV patients, but not total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), or low-density lipoprotein cholesterol (LDL-C). GADD45α expression in HCV patients dramatically decreased with the increase of viral load. In Huh7 cells, FFA treatment significantly enhanced HCV replication. HCV infection inhibited GADD45α expression, and this effect was further enhanced with the presence of FFA treatment. Ectopic expression of GADD45α in HCV-infected Huh7 cells markedly inhibited the absorption of FFA and HCV replication. However, FFA significantly elevated GADD45α expression without HCV infection. CONCLUSIONS These results demonstrated that HCV down-regulates GADD45α expression to enhance FFA absorption and thus facilitate its replication. GADD45α is an essential mediator for the pathogenesis of HCV infection. Thus, our study provides potential clues in the search for novel therapeutics and fatty lipid control options for HCV patients.
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Affiliation(s)
- Wei Chen
- Department of Clinical Laboratory, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
| | - Xiao-Ming Li
- Department of Biochemistry and Molecular Biology, Wuhan University School of Basic Medical Sciences, Wuhan, Hubei, China (mainland)
| | - An-Ling Li
- Department of Clinical laboratory, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
| | - Gui Yang
- Department of Clinical laboratory, Zhongnan Hospital of Wuhan University,, Wuhan, Hubei, China (mainland)
| | - Han-Ning Hu
- Department of Clinical laboratory, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China (mainland)
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22
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Dong H, Rendeiro C, Kristek A, Sargent LJ, Saunders C, Harkness L, Rowland I, Jackson KG, Spencer JP, Lovegrove JA. Addition of Orange Pomace to Orange Juice Attenuates the Increases in Peak Glucose and Insulin Concentrations after Sequential Meal Ingestion in Men with Elevated Cardiometabolic Risk. J Nutr 2016; 146:1197-203. [PMID: 27170728 DOI: 10.3945/jn.115.226001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 04/11/2016] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Prospective cohort studies show that higher dietary fiber intake is associated with reduced cardiovascular disease risk, yet the impact on postprandial glucose and insulin responses is unclear. OBJECTIVE This study aims to evaluate the effects of orange beverages with differing fiber concentrations on postprandial glycemic responses (secondary outcome measure) after a sequential breakfast and lunch challenge in men with increased cardiometabolic risk. METHODS Thirty-six men (aged 30-65 y; body mass index 25-30 kg/m(2): fasting triacylglycerol or total cholesterol concentrations: 0.8-2.2 or 6.0-8.0 mmol/L, respectively) were provided with a high-fat mixed breakfast and were randomly assigned to consume 240 mL Tropicana (PepsiCo, Inc.) pure premium orange juice without pulp (OJ), OJ with 5.5 g added orange pomace fiber (OPF), juice made from lightly blended whole orange, or an isocaloric sugar-matched control (Control) on 4 occasions separated by 2 wk. A medium-fat mixed lunch was provided at 330 min. Blood samples were collected before breakfast and on 11 subsequent occasions for 420 min (3 time points postlunch) to determine postprandial glucose, insulin, lipid, and inflammatory biomarker responses. Repeated-measures ANOVA was used for data analysis. RESULTS OPF significantly (P < 0.05) reduced the maximal change in glucose concentrations (1.9 ± 0.21 mmol/L) reached after breakfast compared with other treatments (2.3-2.4 mmol/L) and after lunch (3.0 ± 0.05 mmol/L) compared with OJ (3.6 ± 0.05 mmol/L). The maximal change in insulin concentration (313 ± 25 pmol/L) was also lower compared with Control (387 ± 30 pmol/L) and OJ (418 ± 39 pmol/L) after breakfast. OPF significantly delayed the time to reach the peak glucose concentration compared with Control and OJ, and of insulin compared with Control after breakfast. CONCLUSION OPF consumed with breakfast may lower postprandial glycemic and insulinemic responses to typical meal ingestion in men with increased cardiometabolic risk. This trial is registered at clinicaltrials.gov as NCT01963416.
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Affiliation(s)
- Honglin Dong
- Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | - Catarina Rendeiro
- Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | - Angelika Kristek
- Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | - Laura J Sargent
- Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | | | | | - Ian Rowland
- Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | - Kim G Jackson
- Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | - Jeremy Pe Spencer
- Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | - Julie A Lovegrove
- Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom;
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Broussard JL, Nelson MD, Kolka CM, Bediako IA, Paszkiewicz RL, Smith L, Szczepaniak EW, Stefanovski D, Szczepaniak LS, Bergman RN. Rapid development of cardiac dysfunction in a canine model of insulin resistance and moderate obesity. Diabetologia 2016; 59:197-207. [PMID: 26376797 PMCID: PMC5310691 DOI: 10.1007/s00125-015-3767-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 08/26/2015] [Indexed: 12/30/2022]
Abstract
AIMS/HYPOTHESIS The worldwide incidence of obesity and diabetes continues to rise at an alarming rate. A major cause of the morbidity and mortality associated with obesity and diabetes is heart disease, yet the mechanisms that lead to cardiovascular complications remain unclear. METHODS We performed cardiac MRI to assess left ventricular morphology and function during the development of moderate obesity and insulin resistance in a well-established canine model (n = 26). To assess the influence of dietary fat composition, we randomised animals to a traditional lard diet (rich in saturated and monounsaturated fat; n = 12), a salmon oil diet (rich in polyunsaturated fat; n = 8) or a control diet (n = 6). RESULTS High-fat feeding with lard increased body weight and fasting insulin and markedly reduced insulin sensitivity. Lard feeding also significantly reduced left ventricular function, evidenced by a worsening of circumferential strain and impairment in left ventricular torsion. High-fat feeding with salmon oil increased body weight; however, salmon oil feeding did not impair insulin sensitivity or cardiac function. CONCLUSIONS/INTERPRETATION These data emphasise the importance of dietary fat composition on both metabolic and cardiac function, and have important implications for the relationship between diet and health.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Michael D Nelson
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Laura Smith
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Edward W Szczepaniak
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Darko Stefanovski
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Lidia S Szczepaniak
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.
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24
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Broussard JL, Kolka CM, Castro AVB, Asare Bediako I, Paszkiewicz RL, Szczepaniak EW, Szczepaniak LS, Knutson KL, Kim SP, Bergman RN. Elevated nocturnal NEFA are an early signal for hyperinsulinaemic compensation during diet-induced insulin resistance in dogs. Diabetologia 2015; 58:2663-70. [PMID: 26254577 PMCID: PMC4591216 DOI: 10.1007/s00125-015-3721-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 07/14/2015] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS A normal consequence of increased energy intake and insulin resistance is compensatory hyperinsulinaemia through increased insulin secretion and/or reduced insulin clearance. Failure of compensatory mechanisms plays a central role in the pathogenesis of type 2 diabetes mellitus; consequently, it is critical to identify in vivo signal(s) involved in hyperinsulinaemic compensation. We have previously reported that high-fat feeding leads to an increase in nocturnal NEFA concentration. We therefore designed this study to test the hypothesis that elevated nocturnal NEFA are an early signal for hyperinsulinaemic compensation for insulin resistance. METHODS Blood sampling was conducted in male dogs to determine 24 h profiles of NEFA at baseline and during high-fat feeding with and without acute nocturnal NEFA suppression using a partial A1 adenosine receptor agonist. RESULTS High-fat feeding increased nocturnal NEFA and reduced insulin sensitivity, effects countered by an increase in acute insulin response to glucose (AIR(g)). Pharmacological NEFA inhibition after 8 weeks of high-fat feeding lowered NEFA to baseline levels and reduced AIR(g) with no effect on insulin sensitivity. A significant relationship emerged between nocturnal NEFA levels and AIR(g). This relationship indicates that the hyperinsulinaemic compensation induced in response to high-fat feeding was prevented when the nocturnal NEFA pattern was returned to baseline. CONCLUSIONS/INTERPRETATION Elevated nocturnal NEFA are an important signal for hyperinsulinaemic compensation during diet-induced insulin resistance.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Ana V B Castro
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Edward W Szczepaniak
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Lidia S Szczepaniak
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | | | - Stella P Kim
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
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25
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Kabir M, Iyer MS, Richey JM, Woolcott OO, Asare Bediako I, Wu Q, Kim SP, Stefanovski D, Kolka CM, Hsu IR, Catalano KJ, Chiu JD, Ionut V, Bergman RN. CB1R antagonist increases hepatic insulin clearance in fat-fed dogs likely via upregulation of liver adiponectin receptors. Am J Physiol Endocrinol Metab 2015; 309:E747-58. [PMID: 26306598 PMCID: PMC4609878 DOI: 10.1152/ajpendo.00196.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/18/2015] [Indexed: 02/06/2023]
Abstract
The improvement of hepatic insulin sensitivity by the cannabinoid receptor 1 (CB1R) antagonist rimonabant (RIM) has been recently been reported to be due to upregulation of adiponectin. Several studies demonstrated that improvement in insulin clearance accompanies the enhancement of hepatic insulin sensitivity. However, the effects of RIM on hepatic insulin clearance (HIC) have not been fully explored. The aim of this study was to explore the molecular mechanism(s) by which RIM affects HIC, specifically to determine whether upregulation of liver adiponectin receptors (ADRs) and other key genes regulated by adiponectin mediate the effects. To induce insulin resistance in skeletal muscle and liver, dogs were fed a hypercaloric high-fat diet (HFD) for 6 wk. Thereafter, while still maintained on a HFD, animals received RIM (HFD+RIM; n = 11) or placebo (HFD+PL; n = 9) for an additional 16 wk. HIC, calculated as the metabolic clearance rate (MCR), was estimated from the euglycemic-hyperinsulinemic clamp. The HFD+PL group showed a decrease in MCR; in contrast, the HFD+RIM group increased MCR. Consistently, the expression of genes involved in HIC, CEACAM-1 and IDE, as well as gene expression of liver ADRs, were increased in the HFD+RIM group, but not in the HFD+PL group. We also found a positive correlation between CEACAM-1 and the insulin-degrading enzyme IDE with ADRs. Interestingly, expression of liver genes regulated by adiponectin and involved in lipid oxidation were increased in the HFD+RIM group. We conclude that in fat-fed dogs RIM enhances HIC, which appears to be linked to an upregulation of the adiponectin pathway.
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MESH Headings
- Animals
- Antigens, CD/drug effects
- Antigens, CD/metabolism
- Cannabinoid Receptor Antagonists/pharmacology
- Cell Adhesion Molecules/drug effects
- Cell Adhesion Molecules/metabolism
- Diet, High-Fat
- Dogs
- Glucose Clamp Technique
- Insulin/metabolism
- Insulin Resistance
- Insulysin/drug effects
- Insulysin/metabolism
- Liver/drug effects
- Liver/metabolism
- Male
- Metabolic Clearance Rate
- Piperidines/pharmacology
- Pyrazoles/pharmacology
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptors, Adiponectin/drug effects
- Receptors, Adiponectin/genetics
- Receptors, Adiponectin/metabolism
- Rimonabant
- Up-Regulation/drug effects
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Affiliation(s)
- Morvarid Kabir
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Malini S Iyer
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Joyce M Richey
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Orison O Woolcott
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Isaac Asare Bediako
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Qiang Wu
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Stella P Kim
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Darko Stefanovski
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Cathryn M Kolka
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Isabel R Hsu
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Karyn J Catalano
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Jenny D Chiu
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Viorica Ionut
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
| | - Richard N Bergman
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, California; and
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26
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Nicol GE, de Las Fuentes L, Riek AE, Bernal-Mizrachi C, Lenze EJ, Miller JP, Schweiger JA, Yingling MD, Huang VJ, Dixon DJ, Hennekens CH, Newcomer JW. Adiposity and Cardiometabolic Risk in Children With and Without Antipsychotic Drug Treatment. J Clin Endocrinol Metab 2015; 100:3418-26. [PMID: 26186300 PMCID: PMC4570158 DOI: 10.1210/jc.2015-2119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
CONTEXT Pediatric obesity is common, particularly in children treated with antipsychotic medications. Antipsychotic exposure can increase cardiometabolic risk by increasing adiposity, and possibly via other adiposity-independent pathways. OBJECTIVE The objectives were to characterize relationships of adiposity with intrahepatic triglyceride (IHTG) content and carotid intima media thickness (CIMT) in children with and without antipsychotic drug treatment, and to explore whether vitamin D alters any effects in these relationships. DESIGN This was a cross-sectional case-control study. SETTING The setting was an academic medical center. PATIENTS OR OTHER PARTICIPANTS Participants were 44 children (ages, 6-19 y): 25 cases treated with antipsychotic and other psychotropic drug therapies and 19 untreated controls, frequency-matched on age, gender, and body mass index. MAIN OUTCOME MEASURES Main outcome measures were dual-energy x-ray absorptiometry percentage body fat (DEXA %fat), IHTG measured by magnetic resonance spectroscopy, and CIMT measured by ultrasonography. Fasting blood glucose, insulin, lipids, C-reactive protein, and liver enzymes were also evaluated. RESULTS There were no significant differences between cases and controls on measures of IHTG, CIMT, or DEXA %fat. In combined crude and adjusted analyses, DEXA %fat predicted IHTG (R(2) = 0.30) but not CIMT. Low levels of vitamin D were associated with larger effects of DEXA %fat on IHTG. CONCLUSION In treated and untreated children alike, adiposity is a significant predictor of liver fat content. This relationship was altered by low vitamin D level. These results suggest a modifiable pathway to hepatic steatosis. Further research is needed to test the hypothesis that children with high adiposity and low vitamin D have particularly increased risks for the development of fatty liver.
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Affiliation(s)
- Ginger E Nicol
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Lisa de Las Fuentes
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Amy E Riek
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Carlos Bernal-Mizrachi
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Eric J Lenze
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - J Phillip Miller
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Julia A Schweiger
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Michael D Yingling
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Vincent J Huang
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - David J Dixon
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Charles H Hennekens
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - John W Newcomer
- Healthy Mind Laboratory, Department of Psychiatry (G.E.N., E.J.L., J.A.S., M.D.Y., V.J.H., D.J.D.), Department of Internal Medicine, Division of Cardiology, Division of Biostatistics (L.d.l.F.), Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research (A.E.R., C.B.-M.), and Division of Biostatistics (J.P.M.), Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110; and Integrated Medical Science Department, First Sir Richard Doll Professor (C.H.H.), and Department of Clinical Biomedical Science (J.W.N.), Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
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Broussard JL, Chapotot F, Abraham V, Day A, Delebecque F, Whitmore HR, Tasali E. Sleep restriction increases free fatty acids in healthy men. Diabetologia 2015; 58:791-8. [PMID: 25702040 PMCID: PMC4358810 DOI: 10.1007/s00125-015-3500-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 12/22/2014] [Indexed: 02/03/2023]
Abstract
AIMS/HYPOTHESIS Sleep loss is associated with insulin resistance and an increased risk for type 2 diabetes, yet underlying mechanisms are not understood. Elevation of circulating non-esterified (i.e. free) fatty acid (NEFA) concentrations can lead to insulin resistance and plays a central role in the development of metabolic diseases. Circulating NEFA in healthy individuals shows a marked diurnal variation with maximum levels occurring at night, yet the impact of sleep loss on NEFA levels across the 24 h cycle remains unknown. We hypothesised that sleep restriction would alter hormones that are known to stimulate lipolysis and lead to an increase in NEFA levels. METHODS We studied 19 healthy young men under controlled laboratory conditions with four consecutive nights of 8.5 h in bed (normal sleep) and 4.5 h in bed (sleep restriction) in randomised order. The 24 h blood profiles of NEFA, growth hormone (GH), noradrenaline (norepinephrine), cortisol, glucose and insulin were simultaneously assessed. Insulin sensitivity was estimated by a frequently sampled intravenous glucose tolerance test. RESULTS Sleep restriction relative to normal sleep resulted in increased NEFA levels during the nocturnal and early-morning hours. The elevation in NEFA was related to prolonged nocturnal GH secretion and higher early-morning noradrenaline levels. Insulin sensitivity was decreased after sleep restriction and the reduction in insulin sensitivity was correlated with the increase in nocturnal NEFA levels. CONCLUSIONS/INTERPRETATION Sleep restriction in healthy men results in increased nocturnal and early-morning NEFA levels, which may partly contribute to insulin resistance and the elevated diabetes risk associated with sleep loss.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, THA E104, Los Angeles, CA, 90048, USA,
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28
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Toledo-Corral CM, Alderete TL, Richey J, Sequeira P, Goran MI, Weigensberg MJ. Fasting, post-OGTT challenge, and nocturnal free fatty acids in prediabetic versus normal glucose tolerant overweight and obese Latino adolescents. Acta Diabetol 2015; 52:277-84. [PMID: 25109287 PMCID: PMC4324370 DOI: 10.1007/s00592-014-0634-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 07/23/2014] [Indexed: 01/16/2023]
Abstract
Type 2 diabetes risk and its relationship to free fatty acid (FFA) exposure and visceral fat by prediabetes status in minority adolescents have yet to be explored. Therefore, the objective of this study was to examine the association of circulating FFA under varying conditions with prediabetes in Latino adolescents and to determine the relative relationships of FFA and visceral adiposity to insulin sensitivity, secretion, and β-cell function. Overweight or obese, but otherwise healthy Latino adolescent males and females (n = 164, 14.2 ± 2.5 years), were recruited for assessment of prediabetes, abdominal fat, and FFA levels taken at a fasting state (FFAF), during an OGTT (FFAOGTT), and overnight (FFANOCTURNAL). Prediabetic adolescents had a higher FFAF than those with normal glucose tolerance when controlling for age, sex, pubertal status, total percent body fat, and visceral fat. FFAOGTT and FFANOCTURNAL did not differ between participants with prediabetes and those with normal glucose tolerance after adjusting for covariates. Visceral fat was independently related to insulin sensitivity and secretion in pubertal adolescents; however, in post-pubertal adolescents, FFAF and visceral fat were both independent and negatively related to β-cell function. These results support a plausible progression of the lipotoxicity theory of diabetes development during the pubertal transition.
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Affiliation(s)
- Claudia M. Toledo-Corral
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033
- Department of Public Health, California State University, Los Angeles; Los Angeles, CA 90032
| | - Tanya L. Alderete
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033
| | - Joyce Richey
- Department of Physiology & Biophysics, University of Southern California, Los Angeles, CA, 90033
| | - Paola Sequeira
- Department of Pediatrics, University of Southern California, Los Angeles, CA, 90033
| | - Michael I. Goran
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033
- Department of Physiology & Biophysics, University of Southern California, Los Angeles, CA, 90033
| | - Marc J. Weigensberg
- Department of Pediatrics, University of Southern California, Los Angeles, CA, 90033
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Raffaelli M, Iaconelli A, Nanni G, Guidone C, Callari C, Fernandez Real JM, Bellantone R, Mingrone G. Effects of biliopancreatic diversion on diurnal leptin, insulin and free fatty acid levels. Br J Surg 2015; 102:682-90. [DOI: 10.1002/bjs.9780] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 11/03/2014] [Accepted: 01/13/2015] [Indexed: 12/25/2022]
Abstract
Abstract
Background
Free fatty acid (FFA) levels are raised in obesity as a consequence of increased production and reduced clearance. They may link obesity with insulin resistance. Bariatric surgery can result in considerable weight loss and reduced insulin resistance, but the mechanism of action is not well understood. Although drugs such as metformin that lower insulin resistance can contribute to weight loss, a better understanding of the links between obesity, weight loss and changes in insulin resistance might lead to new approaches to patient management.
Methods
Variations in circulating levels of leptin, insulin and FFAs over 24 h were studied in severely obese (body mass index over 40 kg/m2) women before and 6 months after biliopancreatic diversion (BPD). Body composition was measured by dual-energy X-ray absorptiometry. A euglycaemic–hyperinsulinaemic clamp was used to assess insulin sensitivity. Levels of insulin, leptin and FFAs were measured every 20 min for 24 h. Pulsatile hormone and FFA analyses were performed.
Results
Among eight patients studied, insulin sensitivity more than doubled after BPD, from mean(s.d.) 39·78(7·74) to 96·66(27·01) mmol per kg fat-free mass per min, under plasma insulin concentrations of 102·29(9·60) and 93·61(9·95) µunits/ml respectively. The secretory patterns of leptin were significantly different from random but not statistically different before and after BPD, with the exception of the pulse height which was reduced after surgery. Both plasma insulin and FFA levels were significantly higher throughout the study day before BPD. Based on Granger statistical modelling, lowering of daily FFA levels was linked to decreased circulating leptin concentrations, which in turn were related to the lowering of daily insulin excursions. Multiple regression analysis indicated that FFA level was the only predictor of leptin level.
Conclusion
Lowering of circulating levels of FFAs after BPD may be responsible for the reduction in leptin secretion, which in turn can decrease circulating insulin levels. Surgical relevanceInsulin resistance is a common feature of obesity and type II diabetes. These patients are also relatively insensitive to the biological effects of leptin, a satiety hormone produced mainly in subcutaneous fat.Biliopancreatic diversion, a malabsorptive bariatric operation that drastically reduces circulating lipid levels, improves insulin resistance independently of weight loss. The mechanism of action, however, has still to be elucidated.This study demonstrated that normalization of insulin sensitivity after bariatric surgery was associated with a reduction in 24-h free fatty acid concentrations and changes in the pattern of leptin peaks in plasma. Bariatric surgery improves the metabolic dysfunction of obesity, and this may be through a reduction in circulating free fatty acids and modification of leptin metabolism.
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Affiliation(s)
- M Raffaelli
- Departments of Surgery, Catholic University of Rome, Rome, Italy
| | - A Iaconelli
- Departments of Internal Medicine, Catholic University of Rome, Rome, Italy
| | - G Nanni
- Departments of Surgery, Catholic University of Rome, Rome, Italy
| | - C Guidone
- Departments of Internal Medicine, Catholic University of Rome, Rome, Italy
| | - C Callari
- Departments of Surgery, Catholic University of Rome, Rome, Italy
| | - J M Fernandez Real
- Biomedical Research Institute of Girona (IDIBGI), CIBERobn Obesity Hospital of Girona ‘Dr Josep Trueta’, Girona, Spain
| | - R Bellantone
- Departments of Surgery, Catholic University of Rome, Rome, Italy
| | - G Mingrone
- Departments of Internal Medicine, Catholic University of Rome, Rome, Italy
- Department of Diabetes and Nutritional Sciences, Faculty of Life Sciences and Medicine, King's College, London, UK
- Medizinische Klinik und Poliklinik III, Universitätsklinikum Carl Gustav Carus an der Technischen Universität Dresden, Dresden, Germany
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30
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Kolka CM, Castro AVB, Kirkman EL, Bergman RN. Modest hyperglycemia prevents interstitial dispersion of insulin in skeletal muscle. Metabolism 2015; 64:330-7. [PMID: 25468139 PMCID: PMC4277905 DOI: 10.1016/j.metabol.2014.10.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 09/22/2014] [Accepted: 10/28/2014] [Indexed: 10/24/2022]
Abstract
UNLABELLED Insulin injected directly into skeletal muscle diffuses rapidly through the interstitial space to cause glucose uptake, but this is blocked in insulin resistance. As glucotoxicity is associated with endothelial dysfunction, the observed hyperglycemia in diet-induced obese dogs may inhibit insulin access to muscle cells, and exacerbate insulin resistance. Here we asked whether interstitial insulin diffusion is reduced in modest hyperglycemia, similar to that induced by a high fat diet. METHODS During normoglycemic (100 mg/dl) and moderately hyperglycemic (120 mg/dl) clamps in anesthetized canines, sequential doses of insulin were injected into the vastus medialis of one hindlimb; the contra-lateral limb served as a control. Plasma samples were collected and analyzed for insulin content. Lymph vessels of the hind leg were also catheterized, and lymph samples were analyzed as an indicator of interstitial insulin concentration. RESULTS Insulin injection increased lymph insulin in normoglycemic animals, but not in hyperglycemic animals. Muscle glucose uptake was elevated in response to hyperglycemia, however the insulin-mediated glucose uptake in normoglycemic controls was not observed in hyperglycemia. Modest hyperglycemia prevented intra-muscularly injected insulin from diffusing through the interstitial space reduced insulin-mediated glucose uptake. CONCLUSION Hyperglycemia prevents the appearance of injected insulin in the interstitial space, thus reducing insulin action on skeletal muscle cells.
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MESH Headings
- Absorption, Physiological
- Animals
- Biological Transport/drug effects
- Diffusion
- Dogs
- Dose-Response Relationship, Drug
- Extracellular Space/chemistry
- Glucose/metabolism
- Glucose Clamp Technique
- Hindlimb
- Hyperglycemia/blood
- Hyperglycemia/drug therapy
- Hyperglycemia/metabolism
- Hyperglycemia/physiopathology
- Hypoglycemic Agents/administration & dosage
- Hypoglycemic Agents/metabolism
- Hypoglycemic Agents/pharmacokinetics
- Hypoglycemic Agents/therapeutic use
- Injections, Intramuscular
- Insulin Resistance
- Insulin, Regular, Pork/administration & dosage
- Insulin, Regular, Pork/analysis
- Insulin, Regular, Pork/pharmacokinetics
- Insulin, Regular, Pork/therapeutic use
- Lymph/chemistry
- Lymph/drug effects
- Male
- Quadriceps Muscle/chemistry
- Quadriceps Muscle/drug effects
- Quadriceps Muscle/metabolism
- Severity of Illness Index
- Tissue Distribution
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Affiliation(s)
- Cathryn M Kolka
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA.
| | - Ana Valeria B Castro
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA
| | - Erlinda L Kirkman
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA
| | - Richard N Bergman
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA
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31
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Castro AV, Woolcott OO, Iyer MS, Kabir M, Ionut V, Stefanovski D, Kolka CM, Szczepaniak LS, Szczepaniak EW, Asare-Bediako I, Paszkiewicz RL, Broussard JL, Kim SP, Kirkman EL, Rios HC, Mkrtchyan H, Wu Q, Ader M, Bergman RN. Increase in visceral fat per se does not induce insulin resistance in the canine model. Obesity (Silver Spring) 2015; 23:105-11. [PMID: 25322680 PMCID: PMC4276477 DOI: 10.1002/oby.20906] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/30/2014] [Indexed: 12/25/2022]
Abstract
OBJECTIVES To determine whether a selective increase of visceral adipose tissue content will result in insulin resistance. METHODS Sympathetic denervation of the omental fat was performed under general inhalant anesthesia by injecting 6-hydroxydopamine in the omental fat of lean mongrel dogs (n = 11). In the conscious animal, whole-body insulin sensitivity was assessed by the minimal model (SI ) and the euglycemic hyperinsulinemic clamp (SICLAMP ). Changes in abdominal fat were monitored by magnetic resonance. All assessments were determined before (Wk0) and 2 weeks (Wk2) after denervation. Data are medians (upper and lower interquartile). RESULTS Denervation of omental fat resulted in increased percentage (and content) of visceral fat [Wk0: 10.2% (8.5-11.4); Wk2: 12.4% (10.4-13.6); P < 0.01]. Abdominal subcutaneous fat remained unchanged. However, no changes were found in SI [Wk0: 4.7 (mU/l)(-1) min(-1) (3.1-8.8); Wk2: 5.3 (mU/l)(-1) min(-1) (4.5-7.2); P = 0.59] or SICLAMP [Wk0: 42.0 × 10(-4) dl kg(-1) min(-1) (mU/l)(-1) (41.0-51.0); Wk2: 40.0 × 10(-4) dl kg(-1) min(-1) (mU/l) (-1) (34.0-52.0); P = 0.67]. CONCLUSIONS Despite a selective increase in visceral adiposity in dogs, insulin sensitivity in vivo did not change, which argues against the concept that accumulation of visceral adipose tissue contributes to insulin resistance.
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Affiliation(s)
- Ana V.B. Castro
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Orison O. Woolcott
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Malini S. Iyer
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Morvarid Kabir
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Viorica Ionut
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Darko Stefanovski
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Cathryn M. Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Lidia S. Szczepaniak
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Edward W. Szczepaniak
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Isaac Asare-Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | | | - Josiane L. Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Stella P. Kim
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Erlinda L. Kirkman
- Department of Animal Resources, University of Southern California, Los Angeles
| | - Hernan C. Rios
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Hasmik Mkrtchyan
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Qiang Wu
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Marilyn Ader
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
| | - Richard N. Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles
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32
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Ferrannini E, Mari A. β-Cell function in type 2 diabetes. Metabolism 2014; 63:1217-27. [PMID: 25070616 DOI: 10.1016/j.metabol.2014.05.012] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/09/2014] [Accepted: 05/25/2014] [Indexed: 01/09/2023]
Abstract
Different in vivo tests explore different aspects of β-cell function. Because intercorrelation of insulin secretion indices is modest, no single in vivo test allows β-cell function to be assessed with accuracy and specificity comparable to insulin sensitivity. Physiologically-based mathematical modeling is necessary to interpret insulin secretory responses in terms of relevant parameters of β-cell function. Models can be used to analyze intravenous glucose tests, but secretory responses to intravenous glucose may be paradoxical in subjects with diabetes. Use of oral glucose (or mixed meal) data may be preferable not only for simplicity but also for physiological interpretation. While the disposition index focuses on the relationship between insulin secretion and insulin resistance, secretion parameters reflecting the dynamic response to changing glucose levels over a time frame of minutes or hours--such as β-cell glucose sensitivity--are key to explain changes in glucose tolerance and are largely independent of insulin sensitivity. Pathognomonic of the β-cell defect of type 2 diabetes is a reduced glucose sensitivity, which is accompanied by normal or raised absolute insulin secretion rates--compensatory to the attendant insulin resistance--and impaired incretin-induced potentiation. As β-cell mass is frequently within the range of nondiabetic individuals, these defects are predominantly functional and potentially reversible. Any intervention, on lifestyle or with drugs, that improves glucose tolerance does so primarily through increased β-cell glucose sensitivity. So far, however, no intervention has proven unequivocally capable of modifying the natural course of β-cell dysfunction.
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Affiliation(s)
- Ele Ferrannini
- Department of Clinical & Experimental Medicine, University of Pisa, Italy.
| | - Andrea Mari
- C N R Institute of Biomedical Engineering, Padova, Italy
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33
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Effects of Korean red ginseng supplementation on muscle glucose uptake in high-fat fed rats. Chin J Nat Med 2014; 11:494-9. [PMID: 24359773 DOI: 10.1016/s1875-5364(13)60090-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Indexed: 11/21/2022]
Abstract
It has been recognized that ginseng has anti-diabetic effects in skeletal muscle, but the mechanism has not been intensively investigated. The aim of this study was to investigate the effects of Korean red ginseng (Panax ginseng) supplementation on muscle glucose uptake in high-fat fed rats. Sixteen rats were randomly divided into two groups: a control group (CON, n = 8) and a Korean red ginseng group (KRG, n = 8). The KRG group ingested RG extract (1 g·kg(-1), 6 days/week) mixed in water for two weeks. After the two-week treatment, plasma lipid profiles, and glucose and insulin concentrations were measured. The triglyceride (TG) and glucose transporter 4 (GLUT-4) contents were measured in the skeletal muscle and liver. The rate of glucose transport was determined under a submaximal insulin concentration during muscle incubation. Plasma FFA concentrations were significantly decreased in KRG (P < 0.05). Liver and muscle triglyceride concentrations were also decreased in the KRG treatment group (P < 0.05) compared to the CON group. In addition, resting plasma insulin and glucose levels were significantly lower after Korean red ginseng treatment (P < 0.05). However, muscle glucose uptake was not affected by Korean red ginseng treatment, as evidenced by the rate of glucose transport in the epitorchealis muscle under submaximal insulin concentrations. These results suggest that while KRG supplementation could improve whole body insulin resistance and plasma lipid profiles, it is unlikely to have an effect on the insulin resistance of skeletal muscle, which is the major tissue responsible for plasma glucose handling.
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34
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Bergman RN, Stefanovski D, Kim SP. Systems analysis and the prediction and prevention of Type 2 diabetes mellitus. Curr Opin Biotechnol 2014; 28:165-70. [PMID: 24976265 PMCID: PMC5931209 DOI: 10.1016/j.copbio.2014.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/29/2014] [Accepted: 05/30/2014] [Indexed: 01/22/2023]
Abstract
Prevalence of Type 2 diabetes has increased at an alarming rate, highlighting the need to correctly predict the development of this disease in order to allow intervention and thus, slow progression of the disease and resulting metabolic derangement. There have been many recent 'advances' geared toward the detection of pre-diabetes, including genome wide association studies and metabolomics. Although these approaches generate a large amount of data with a single blood sample, studies have indicated limited success using genetic and metabolomics information alone for identification of disease risk. Clinical assessment of the disposition index (DI), based on the hyperbolic law of glucose tolerance, is a powerful predictor of Type 2 diabetes, but is not easily assessed in the clinical setting. Thus, it is evident that combining genetic or metabolomic approaches for a more simple assessment of DI may provide a useful tool to identify those at highest risk for Type 2 diabetes, allowing for intervention and prevention.
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Affiliation(s)
- Richard N Bergman
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA 90048, USA.
| | - Darko Stefanovski
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA 90048, USA
| | - Stella P Kim
- Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA 90048, USA
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35
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Ader M, Stefanovski D, Kim SP, Richey JM, Ionut V, Catalano KJ, Hucking K, Ellmerer M, Van Citters G, Hsu IR, Chiu JD, Woolcott OO, Harrison LN, Zheng D, Lottati M, Kolka CM, Mooradian V, Dittmann J, Yae S, Liu H, Castro AVB, Kabir M, Bergman RN. Hepatic insulin clearance is the primary determinant of insulin sensitivity in the normal dog. Obesity (Silver Spring) 2014; 22:1238-45. [PMID: 24123967 PMCID: PMC3969862 DOI: 10.1002/oby.20625] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 08/15/2013] [Accepted: 09/10/2013] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Insulin resistance is a powerful risk factor for Type 2 diabetes and a constellation of chronic diseases, and is most commonly associated with obesity. We examined if factors other than obesity are more substantial predictors of insulin sensitivity under baseline, nonstimulated conditions. METHODS Metabolic assessment was performed in healthy dogs (n = 90). Whole-body sensitivity from euglycemic clamps (SICLAMP ) was the primary outcome variable, and was measured independently by IVGTT (n = 36). Adiposity was measured by MRI (n = 90), and glucose-stimulated insulin response was measured from hyperglycemic clamp or IVGTT (n = 86 and 36, respectively). RESULTS SICLAMP was highly variable (5.9-75.9 dl/min per kg per μU/ml). Despite narrow range of body weight (mean, 28.7 ± 0.3 kg), adiposity varied approximately eight-fold and was inversely correlated with SICLAMP (P < 0.025). SICLAMP was negatively associated with fasting insulin, but most strongly associated with insulin clearance. Clearance was the dominant factor associated with sensitivity (r = 0.53, P < 0.00001), whether calculated from clamp or IVGTT. CONCLUSIONS These data suggest that insulin clearance contributes substantially to insulin sensitivity, and may be pivotal in understanding the pathogenesis of insulin resistance. We propose the hyperinsulinemia due to reduction in insulin clearance is responsible for insulin resistance secondary to changes in body weight.
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Affiliation(s)
- Marilyn Ader
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
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36
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Magkos F, Smith GI, Reeds DN, Okunade A, Patterson BW, Mittendorfer B. One day of overfeeding impairs nocturnal glucose but not fatty acid homeostasis in overweight men. Obesity (Silver Spring) 2014; 22:435-40. [PMID: 23836730 PMCID: PMC3849339 DOI: 10.1002/oby.20562] [Citation(s) in RCA: 10] [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: 04/02/2013] [Revised: 06/09/2013] [Accepted: 06/26/2013] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Overfeeding is associated with insulin resistance. Studies on animals suggest this is likely due to disruption of fatty acid metabolism and increased plasma free fatty acid (FFA) availability during the night. We tested the hypothesis that overfeeding induces insulin resistance and increases nocturnal but not daytime plasma FFA availability in human subjects. DESIGN AND METHODS We measured plasma glucose, insulin, and FFA concentrations hourly for 24 h during a day of isocaloric feeding and a day of hypercaloric feeding (30% calorie excess) in 8 overweight and obese, nondiabetic men (age: 38±3 years; body mass index: 34±2 kg/m²). RESULTS Overfeeding had no effect on daytime plasma glucose, insulin, and FFA concentrations compared to isocaloric feeding, but increased nocturnal glucose (P = 0.007) and insulin (P = 0.003) concentrations and decreased nocturnal FFA concentration (P = 0.006). The homeostasis model assessment of insulin resistance score was ∼30% greater the morning after hypercaloric than isocaloric feeding (P = 0.040). CONCLUSIONS One day of overfeeding has no effect on daytime plasma glucose and FFA concentrations but increases nocturnal plasma glucose and insulin concentrations, whereas nocturnal plasma FFA availability is reduced. The acute overfeeding-induced development of insulin resistant glucose metabolism therefore does not appear to be directly mediated by plasma FFA availability.
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Affiliation(s)
- Faidon Magkos
- Division of Geriatrics and Nutritional Science, Center for Human Nutrition, Washington University School of Medicine, St. Louis, Missouri, USA
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37
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Biet M, Morin N, Benrezzak O, Naimi F, Bellanger S, Baillargeon JP, Chouinard L, Gallo-Payet N, Carpentier AC, Dumaine R. Lasting alterations of the sodium current by short-term hyperlipidemia as a mechanism for initiation of cardiac remodeling. Am J Physiol Heart Circ Physiol 2014; 306:H291-7. [DOI: 10.1152/ajpheart.00715.2013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Clinical and animal studies indicate that increased fatty acid delivery to lean tissues induces cardiac electrical remodeling and alterations of cellular calcium homeostasis. Since this may represent a mechanism initiating cardiac dysfunction during establishment of insulin resistance and diabetes or anaerobic cardiac metabolism (ischemia), we sought to determine if short-term exposure to high plasma concentration of fatty acid in vivo was sufficient to alter the cardiac sodium current ( INa) in dog ventricular myocytes. Our results show that delivery of triglycerides and nonesterified fatty acids by infusion of Intralipid + heparin (IH) for 8 h increased the amplitude of INa by 43% and shifted its activation threshold by −5 mV, closer to the resting membrane potential. Steady-state inactivation (availability) of the channels was reduced by IH with no changes in recovery from inactivation. As a consequence, INa “window” current, a strong determinant of intracellular Na+ and Ca2+ concentrations, was significantly increased. The results indicate that increased circulating fatty acids alter INa gating in manners consistent with an increased cardiac excitability and augmentation of intracellular calcium. Moreover, these changes could still be measured after the dogs were left to recover for 12 h after IH perfusion, suggesting lasting changes in INa. Our results indicate that fatty acids rapidly induce cardiac remodeling and suggest that this process may be involved in the development of cardiac dysfunctions associated to insulin resistance and diabetes.
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Affiliation(s)
- M. Biet
- Department of Physiology and Biophysics, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada; and
| | - N. Morin
- Department of Physiology and Biophysics, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada; and
| | - O. Benrezzak
- Department of Medecine (Endocrinology), Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - F. Naimi
- Department of Physiology and Biophysics, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada; and
| | - S. Bellanger
- Department of Physiology and Biophysics, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada; and
| | - J. P. Baillargeon
- Department of Medecine (Endocrinology), Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - L. Chouinard
- Department of Medecine (Endocrinology), Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - N. Gallo-Payet
- Department of Medecine (Endocrinology), Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - A. C. Carpentier
- Department of Medecine (Endocrinology), Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - R. Dumaine
- Department of Physiology and Biophysics, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada; and
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Gyllenhammer LE, Alderete TL, Mahurka S, Allayee H, Goran MI. Adipose tissue 11βHSD1 gene expression, βcell function and ectopic fat in obese African Americans versus Hispanics. Obesity (Silver Spring) 2014; 22:14-8. [PMID: 23836520 DOI: 10.1002/oby.20571] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 06/21/2013] [Indexed: 12/20/2022]
Abstract
OBJECTIVE This study examined the contribution of subcutaneous adipose tissue (SAT) 11βHSD1 to obese African Americans' (AA) elevated metabolic risk, despite a protective obesity phenotype of reduced visceral adipose tissue (VAT) and hepatic fat fraction (HFF) relative to obese Hispanics with similar metabolic risk. DESIGN AND METHODS Obese AA and Hispanic adults (N = 36(16AA); BMI 35.2 ± 0.6 kg/m(2) , 18-25y) participated, with VAT, SAT, and HFF measured by MRI, SAT gene expression measured by HT-12 microarray and insulin sensitivity (SI), disposition index (DI) by IVGTT. Multiple linear regression examined relationships/interactions of ethnicity and 11βHSD1 expression on outcomes (covariates: age, sex, total fat mass), with standardized β (stβ) reported. RESULTS SAT 11βHSD1 expression significantly associated with insulin parameters and this varied by ethnicity (Pinteraction <0.1). In AA, 11βHSD1 negatively associated with SI (stβ = -0.58, P = 0.03), DI (stβ = -0.62, P = 0.03) and positively associated with fasting insulin (stβ = 0.54, P = 0.04), with no significant relationship in Hispanics. SAT 11βHSD1 associated with HFF in the combined sample (stβ = 0.42, P = 0.008), with no difference between ethnicites (Pinteraction >0.1). After controlling for HFF, 11βHSD1 associations with metabolic risk in AA became nonsignificant. CONCLUSIONS These results suggested that in AA and not Hispanics, SAT 11βHSD1 is associated with SI and DI, and may be mediated by HFF.
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Affiliation(s)
- Lauren E Gyllenhammer
- Department of Preventive Medicine, Diabetes and Obesity Research Institute, University of Southern California, Los Angeles, California, USA
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Shatwan IA, Ahmed LA, Badkook MM. Effect of Barley Flour, Crude Cinnamon, and Their Combination on Glycemia, Dyslipidemia, and Adipose Tissue Hormones in Type 2 Diabetic Rats. J Med Food 2013; 16:656-62. [DOI: 10.1089/jmf.2012.0083] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Israa Ali Shatwan
- Food and Nutrition Department, Faculty of Home Economics, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Lamiaa Ali Ahmed
- Nutrition and Food Science Department, Faculty of Home Economics, Helwan University, Cairo, Egypt
| | - Maha Mohamed Badkook
- Food and Nutrition Department, Faculty of Home Economics, King Abdulaziz University, Jeddah, Saudi Arabia
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Stamateris RE, Sharma RB, Hollern DA, Alonso LC. Adaptive β-cell proliferation increases early in high-fat feeding in mice, concurrent with metabolic changes, with induction of islet cyclin D2 expression. Am J Physiol Endocrinol Metab 2013; 305:E149-59. [PMID: 23673159 PMCID: PMC3725565 DOI: 10.1152/ajpendo.00040.2013] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 05/10/2013] [Indexed: 01/09/2023]
Abstract
Type 2 diabetes (T2D) is caused by relative insulin deficiency, due in part to reduced β-cell mass (11, 62). Therapies aimed at expanding β-cell mass may be useful to treat T2D (14). Although feeding rodents a high-fat diet (HFD) for an extended period (3-6 mo) increases β-cell mass by inducing β-cell proliferation (16, 20, 53, 54), evidence suggests that adult human β-cells may not meaningfully proliferate in response to obesity. The timing and identity of the earliest initiators of the rodent compensatory growth response, possible therapeutic targets to drive proliferation in refractory human β-cells, are not known. To develop a model to identify early drivers of β-cell proliferation, we studied mice during the first week of HFD exposure, determining the onset of proliferation in the context of diet-related physiological changes. Within the first week of HFD, mice consumed more kilocalories, gained weight and fat mass, and developed hyperglycemia, hyperinsulinemia, and glucose intolerance due to impaired insulin secretion. The β-cell proliferative response also began within the first week of HFD feeding. Intriguingly, β-cell proliferation increased before insulin resistance was detected. Cyclin D2 protein expression was increased in islets by day 7, suggesting it may be an early effector driving compensatory β-cell proliferation in mice. This study defines the time frame and physiology to identify novel upstream regulatory signals driving mouse β-cell mass expansion, in order to explore their efficacy, or reasons for inefficacy, in initiating human β-cell proliferation.
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Affiliation(s)
- Rachel E Stamateris
- Division of Diabetes, University of Massachusetts Medical School, Worcester, MA, USA
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Abstract
Excess intra-abdominal adipose tissue accumulation, often termed visceral obesity, is part of a phenotype including dysfunctional subcutaneous adipose tissue expansion and ectopic triglyceride storage closely related to clustering cardiometabolic risk factors. Hypertriglyceridemia; increased free fatty acid availability; adipose tissue release of proinflammatory cytokines; liver insulin resistance and inflammation; increased liver VLDL synthesis and secretion; reduced clearance of triglyceride-rich lipoproteins; presence of small, dense LDL particles; and reduced HDL cholesterol levels are among the many metabolic alterations closely related to this condition. Age, gender, genetics, and ethnicity are broad etiological factors contributing to variation in visceral adipose tissue accumulation. Specific mechanisms responsible for proportionally increased visceral fat storage when facing positive energy balance and weight gain may involve sex hormones, local cortisol production in abdominal adipose tissues, endocannabinoids, growth hormone, and dietary fructose. Physiological characteristics of abdominal adipose tissues such as adipocyte size and number, lipolytic responsiveness, lipid storage capacity, and inflammatory cytokine production are significant correlates and even possible determinants of the increased cardiometabolic risk associated with visceral obesity. Thiazolidinediones, estrogen replacement in postmenopausal women, and testosterone replacement in androgen-deficient men have been shown to favorably modulate body fat distribution and cardiometabolic risk to various degrees. However, some of these therapies must now be considered in the context of their serious side effects. Lifestyle interventions leading to weight loss generally induce preferential mobilization of visceral fat. In clinical practice, measuring waist circumference in addition to the body mass index could be helpful for the identification and management of a subgroup of overweight or obese patients at high cardiometabolic risk.
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Affiliation(s)
- André Tchernof
- Endocrinology and Genomics Axis, Centre Hospitalier Universitaire de Québec, Québec, Canada
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Adipose tissue heterogeneity: implication of depot differences in adipose tissue for obesity complications. Mol Aspects Med 2012; 34:1-11. [PMID: 23068073 DOI: 10.1016/j.mam.2012.10.001] [Citation(s) in RCA: 525] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Obesity, defined as excess fat mass, increases risks for multiple metabolic diseases, such as type 2 diabetes, cardiovascular disease and several types of cancer. Over and above fat mass per se, the pattern of fat distribution, android or truncal as compared to gynoid or peripheral, has a profound influence on systemic metabolism and hence risk for metabolic diseases. Increases in upper body adipose tissue (visceral and abdominal subcutaneous) confer an independent risk, while the quantity of gluteofemoral adipose tissue is protective. Variations in the capacity of different depots to store and release fatty acids and to produce adipokines are important determinants of fat distribution and its metabolic consequences. Depot differences in cellular composition and physiology, including innervation and blood flow, likely influence their phenotypic properties. A number of lines of evidence also support the idea that adipocytes from different anatomical depots are intrinsically different as a result of genetic or developmental events. In this chapter, we will review the phenotypic characteristics of different adipose depots and mechanisms that link their depot-specific biology to metabolic complications in men and women.
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Kim SP, Woolcott OO, Hsu IR, Stefanoski D, Harrison LN, Zheng D, Lottati M, Kolka C, Catalano KJ, Chiu JD, Kabir M, Ionut V, Bergman RN, Richey JM. CB(1) antagonism restores hepatic insulin sensitivity without normalization of adiposity in diet-induced obese dogs. Am J Physiol Endocrinol Metab 2012; 302:E1261-8. [PMID: 22374758 PMCID: PMC3361982 DOI: 10.1152/ajpendo.00496.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The endocannabinoid system is highly implicated in the development of insulin resistance associated with obesity. It has been shown that antagonism of the CB(1) receptor improves insulin sensitivity (S(I)). However, it is unknown whether this improvement is due to the direct effect of CB(1) blockade on peripheral tissues or secondary to decreased fat mass. Here, we examine in the canine dog model the longitudinal changes in S(I) and fat deposition when obesity was induced with a high-fat diet (HFD) and animals were treated with the CB(1) antagonist rimonabant. S(I) was assessed (n = 20) in animals fed a HFD for 6 wk to establish obesity. Thereafter, while HFD was continued for 16 additional weeks, animals were divided into two groups: rimonabant (1.25 mg·kg(-1)·day(-1) RIM; n = 11) and placebo (n = 9). Euglycemic hyperinsulinemic clamps were performed to evaluate changes in insulin resistance and glucose turnover before HFD (week -6) after HFD but before treatment (week 0) and at weeks 2, 6, 12, and 16 of treatment (or placebo) + HFD. Magnetic resonance imaging was performed to determine adiposity- related changes in S(I). Animals developed significant insulin resistance and increased visceral and subcutaneous adiposity after 6 wk of HFD. Treatment with RIM resulted in a modest decrease in total trunk fat with relatively little change in peripheral glucose uptake. However, there was significant improvement in hepatic insulin resistance after only 2 wk of RIM treatment with a concomitant increase in plasma adiponectin levels; both were maintained for the duration of the RIM treatment. CB(1) receptor antagonism appears to have a direct effect on hepatic insulin sensitivity that may be mediated by adiponectin and independent of pronounced reductions in body fat. However, the relatively modest effect on peripheral insulin sensitivity suggests that significant improvements may be secondary to reduced fat mass.
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Affiliation(s)
- Stella P Kim
- Dept. of Physiology and Biophysics, Univ. of Southern California Keck School of Medicine, 1333 San Pablo St. MMR 626, Los Angeles, CA 90033, USA.
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Maki KC, Pelkman CL, Finocchiaro ET, Kelley KM, Lawless AL, Schild AL, Rains TM. Resistant starch from high-amylose maize increases insulin sensitivity in overweight and obese men. J Nutr 2012; 142:717-23. [PMID: 22357745 PMCID: PMC3301990 DOI: 10.3945/jn.111.152975] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This study evaluated the effects of 2 levels of intake of high-amylose maize type 2 resistant starch (HAM-RS2) on insulin sensitivity (S(I)) in participants with waist circumference ≥89 (women) or ≥102 cm (men). Participants received 0 (control starch), 15, or 30 g/d (double-blind) of HAM-RS2 in random order for 4-wk periods separated by 3-wk washouts. Minimal model S(I) was assessed at the end of each period using the insulin-modified i.v. glucose tolerance test. The efficacy evaluable sample included 11 men and 22 women (mean ± SEM) age 49.5 ± 1.6 y, with a BMI of 30.6 ± 0.5 kg/m2 and waist circumference 105.3 ± 1.3 cm. A treatment main effect (P = 0.018) and a treatment × sex interaction (P = 0.033) were present. In men, least squares geometric mean analysis for S(I) did not differ after intake of 15 g/d HAM-RS2 (6.90 × 10⁻⁵ pmol⁻¹ · L⁻¹ × min⁻¹) and 30 g/d HAM-RS2 (7.13 × 10⁻⁵ pmol⁻¹ · L⁻¹ × min⁻¹), but both were higher than after the control treatment (4.66 × 10⁻⁵ pmol⁻¹ · L⁻¹ × min⁻¹) (P < 0.05). In women, there was no difference among the treatments (overall least squares ln-transformed mean ± pooled SEM = 1.80 ± 0.08; geometric mean = 6.05 × 10⁻⁵ pmol⁻¹ · L⁻¹ × min⁻¹). These results suggest that consumption of 15-30 g/d of HAM-RS2 improves S(I) in men. Additional research is needed to understand the mechanisms that might account for the treatment × sex interaction observed.
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Affiliation(s)
- Kevin C. Maki
- Provident Clinical Research and Consulting, Inc., Glen Ellyn, IL; and,To whom correspondence should be addressed. E-mail:
| | | | | | | | - Andrea L. Lawless
- Provident Clinical Research and Consulting, Inc., Glen Ellyn, IL; and
| | - Arianne L. Schild
- Provident Clinical Research and Consulting, Inc., Glen Ellyn, IL; and
| | - Tia M. Rains
- Provident Clinical Research and Consulting, Inc., Glen Ellyn, IL; and
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Pascoe J, Hollern D, Stamateris R, Abbasi M, Romano LC, Zou B, O’Donnell CP, Garcia-Ocana A, Alonso LC. Free fatty acids block glucose-induced β-cell proliferation in mice by inducing cell cycle inhibitors p16 and p18. Diabetes 2012; 61:632-41. [PMID: 22338094 PMCID: PMC3282818 DOI: 10.2337/db11-0991] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Pancreatic β-cell proliferation is infrequent in adult humans and is not increased in type 2 diabetes despite obesity and insulin resistance, suggesting the existence of inhibitory factors. Free fatty acids (FFAs) may influence proliferation. In order to test whether FFAs restrict β-cell proliferation in vivo, mice were intravenously infused with saline, Liposyn II, glucose, or both, continuously for 4 days. Lipid infusion did not alter basal β-cell proliferation, but blocked glucose-stimulated proliferation, without inducing excess β-cell death. In vitro exposure to FFAs inhibited proliferation in both primary mouse β-cells and in rat insulinoma (INS-1) cells, indicating a direct effect on β-cells. Two of the fatty acids present in Liposyn II, linoleic acid and palmitic acid, both reduced proliferation. FFAs did not interfere with cyclin D2 induction or nuclear localization by glucose, but increased expression of inhibitor of cyclin dependent kinase 4 (INK4) family cell cycle inhibitors p16 and p18. Knockdown of either p16 or p18 rescued the antiproliferative effect of FFAs. These data provide evidence for a novel antiproliferative form of β-cell glucolipotoxicity: FFAs restrain glucose-stimulated β-cell proliferation in vivo and in vitro through cell cycle inhibitors p16 and p18. If FFAs reduce proliferation induced by obesity and insulin resistance, targeting this pathway may lead to new treatment approaches to prevent diabetes.
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Affiliation(s)
- Jordan Pascoe
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Douglas Hollern
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rachel Stamateris
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Munira Abbasi
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Lia C. Romano
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Baobo Zou
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Christopher P. O’Donnell
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Adolfo Garcia-Ocana
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Laura C. Alonso
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
- Corresponding author: Laura C. Alonso,
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Cheng L, Khoo MCK. Modeling the autonomic and metabolic effects of obstructive sleep apnea: a simulation study. Front Physiol 2012; 2:111. [PMID: 22291654 PMCID: PMC3250672 DOI: 10.3389/fphys.2011.00111] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 12/09/2011] [Indexed: 01/12/2023] Open
Abstract
Long-term exposure to intermittent hypoxia and sleep fragmentation introduced by recurring obstructive sleep apnea (OSA) has been linked to subsequent cardiovascular disease and Type 2 diabetes. The underlying mechanisms remain unclear, but impairment of the normal interactions among the systems that regulate autonomic and metabolic function is likely involved. We have extended an existing integrative model of respiratory, cardiovascular, and sleep-wake state control, to incorporate a sub-model of glucose-insulin-fatty acid regulation. This computational model is capable of simulating the complex dynamics of cardiorespiratory control, chemoreflex and state-related control of breath-to-breath ventilation, state-related and chemoreflex control of upper airway potency, respiratory and circulatory mechanics, as well as the metabolic control of glucose-insulin dynamics and its interactions with the autonomic control. The interactions between autonomic and metabolic control include the circadian regulation of epinephrine secretion, epinephrine regulation on dynamic fluctuations in glucose and free-fatty acid in plasma, metabolic coupling among tissues and organs provided by insulin and epinephrine, as well as the effect of insulin on peripheral vascular sympathetic activity. These model simulations provide insight into the relative importance of the various mechanisms that determine the acute and chronic physiological effects of sleep-disordered breathing. The model can also be used to investigate the effects of a variety of interventions, such as different glucose clamps, the intravenous glucose tolerance test, and the application of continuous positive airway pressure on OSA subjects. As such, this model provides the foundation on which future efforts to simulate disease progression and the long-term effects of pharmacological intervention can be based.
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Affiliation(s)
- Limei Cheng
- Biomedical Engineering Department, University of Southern California Los Angeles, CA, USA
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Kabir M, Stefanovski D, Hsu IR, Iyer M, Woolcott OO, Zheng D, Catalano KJ, Chiu JD, Kim SP, Harrison LN, Ionut V, Lottati M, Bergman RN, Richey JM. Large size cells in the visceral adipose depot predict insulin resistance in the canine model. Obesity (Silver Spring) 2011; 19:2121-9. [PMID: 21836643 PMCID: PMC4423825 DOI: 10.1038/oby.2011.254] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Adipocyte size plays a key role in the development of insulin resistance. We examined longitudinal changes in adipocyte size and distribution in visceral (VIS) and subcutaneous (SQ) fat during obesity-induced insulin resistance and after treatment with CB-1 receptor antagonist, rimonabant (RIM) in canines. We also examined whether adipocyte size and/or distribution is predictive of insulin resistance. Adipocyte morphology was assessed by direct microscopy and analysis of digital images in previously studied animals 6 weeks after high-fat diet (HFD) and 16 weeks of HFD + placebo (PL; n = 8) or HFD + RIM (1.25 mg/kg/day; n = 11). At 6 weeks, mean adipocyte diameter increased in both depots with a bimodal pattern only in VIS. Sixteen weeks of HFD+PL resulted in four normally distributed cell populations in VIS and a bimodal pattern in SQ. Multilevel mixed-effects linear regression with random-effects model of repeated measures showed that size combined with share of adipocytes >75 µm in VIS only was related to hepatic insulin resistance. VIS adipocytes >75 µm were predictive of whole body and hepatic insulin resistance. In contrast, there was no predictive power of SQ adipocytes >75 µm regarding insulin resistance. RIM prevented the formation of large cells, normalizing to pre-fat status in both depots. The appearance of hypertrophic adipocytes in VIS is a critical predictor of insulin resistance, supporting the deleterious effects of increased VIS adiposity in the pathogenesis of insulin resistance.
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Affiliation(s)
- Morvarid Kabir
- Department of Physiology and Biophysics, University of Southern California, Keck School of Medicine, Los Angeles, California, USA.
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Kador PF, Webb TR, Bras D, Ketring K, Wyman M. Topical KINOSTAT™ ameliorates the clinical development and progression of cataracts in dogs with diabetes mellitus. Vet Ophthalmol 2011; 13:363-8. [PMID: 21182720 DOI: 10.1111/j.1463-5224.2010.00826.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To determine whether topical administration of the aldose reductase inhibitor Kinostat™ can ameliorate the onset or progression of cataracts in dogs with naturally occurring diabetes mellitus (DM). MATERIALS AND METHODS A randomized, prospective, double-masked placebo control pilot study was conducted with 40 dogs newly diagnosed with DM with no or minimal lens changes. Twenty-eight dogs received Kinostat™ and 12 dogs received placebo. PROCEDURES Owners administered the agent into both eyes three times daily for 1 year and compliance was monitored with log sheets. Complete ophthalmic examinations were performed on dilated eyes at the time of enrollment and 1, 2, 3, 6, and 12 months into treatment. Cataract severity was assessed on a scale of 0-3. At 12 months, full bloodwork, including HbA1C and blood Kinostat™ levels were performed. RESULTS After 12 months of treatment, the cataract score in the placebo group significantly increased with seven dogs (14 eyes) developing mature cataracts, two dogs (4 eyes) developing cortical opacities, and one dog (2 eyes) developing equatorial vacuoles with mild punctate cortical opacities. In contrast, the cataract score in the Kinostat™ treated dogs was significantly less with seven developing anterior equatorial vacuoles, two developing incipient anterior cortical cataracts, and four developing mature cataracts. In fact, the cataract scores of the Kinostat™ group at 12 months did not significantly increase from the score at the time of enrollment. The HbA1C values between the two groups after 12 months of treatment were similar, and no blood levels of Kinostat™ were found in any enrolled dog. CONCLUSION The onset and/or progression of cataracts in dogs with DM can be significantly delayed by topical administration of Kinostat™.
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Stefanovski D, Richey JM, Woolcott O, Lottati M, Zheng D, Harrison LN, Ionut V, Kim SP, Hsu I, Bergman RN. Consistency of the disposition index in the face of diet induced insulin resistance: potential role of FFA. PLoS One 2011; 6:e18134. [PMID: 21479217 PMCID: PMC3068147 DOI: 10.1371/journal.pone.0018134] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 02/25/2011] [Indexed: 12/20/2022] Open
Abstract
Objective Insulin resistance induces hyperinsulinemic compensation, which in turn maintains almost a constant disposition index. However, the signal that gives rise to the hyperinsulinemic compensation for insulin resistance remains unknown. Methods In a dog model of obesity we examined the possibility that potential early-week changes in plasma FFA, glucose, or both could be part of a cascade of signals that lead to compensatory hyperinsulinemia induced by insulin resistance. Results Hypercaloric high fat feeding in dogs resulted in modest weight gain, and an increase in adipose tissue with no change in the non-adipose tissue size. To compensate for the drop in insulin sensitivity, there was a significant rise in plasma insulin, which can be attributed in part to a decrease in the metabolic clearance rate of insulin and increased insulin secretion. In this study we observed complete compensation for high fat diet induced insulin resistance as measured by the disposition index. The compensatory hyperinsulinemia was coupled with significant changes in plasma FFAs and no change in plasma glucose. Conclusions We postulate that early in the development of diet induced insulin resistance, a change in plasma FFAs may directly, through signaling at the level of β-cell, or indirectly, by decreasing hepatic insulin clearance, result in the observed hyperinsulinemic compensation.
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Affiliation(s)
- Darko Stefanovski
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America.
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Coate KC, Scott M, Farmer B, Moore MC, Smith M, Roop J, Neal DW, Williams P, Cherrington AD. Chronic consumption of a high-fat/high-fructose diet renders the liver incapable of net hepatic glucose uptake. Am J Physiol Endocrinol Metab 2010; 299:E887-98. [PMID: 20823448 PMCID: PMC3006253 DOI: 10.1152/ajpendo.00372.2010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The objective of this study was to assess the response of a large animal model to high dietary fat and fructose (HFFD). Three different metabolic assessments were performed during 13 wk of feeding an HFFD (n = 10) or chow control (CTR, n = 4) diet: oral glucose tolerance tests (OGTTs; baseline, 4 and 8 wk), hyperinsulinemic-euglycemic clamps (HIEGs; baseline and 10 wk) and hyperinsulinemic-hyperglycemic clamps (HIHGs, 13 wk). The ΔAUC for glucose during the OGTTs more than doubled after 4 and 8 wk of HFFD feeding, and the average glucose infusion rate required to maintain euglycemia during the HIEG clamps decreased by ≈30% after 10 wk of HFFD feeding. These changes did not occur in the CTR group. The HIHG clamps included experimental periods 1 (P1, 0-90 min) and 2 (P2, 90-180 min). During P1, somatostatin, basal intraportal glucagon, 4 × basal intraportal insulin, and peripheral glucose (to double the hepatic glucose load) were infused; during P2, glucose was also infused intraportally (4.0 mg·kg(-1)·min(-1)). Net hepatic glucose uptake during P1 and P2 was -0.4 ± 0.1 [output] and 0.2 ± 0.8 mg·kg(-1)·min(-1) in the HFFD group, respectively, and 1.8 ± 0.8 and 3.5 ± 1.0 mg·kg(-1)·min(-1) in the CTR group, respectively (P < 0.05 vs. HFFD during P1 and P2). Glycogen synthesis through the direct pathway was 0.5 ± 0.2 and 1.5 ± 0.4 mg·kg(-1)·min(-1) in the HFFD and CTR groups, respectively (P < 0.05 vs. HFFD). In conclusion, chronic consumption of an HFFD diminished the sensitivity of the liver to hormonal and glycemic cues and resulted in a marked impairment in NHGU and glycogen synthesis.
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