|Obesity & Diabetes|
Abdominal Fat Measurement: MRS vs. MRI
Min-Hui Cui1, 2, Vlad Tomuta1, CJ Segal-Isaacson1, Daniel T. Stein1, Jong-Hee Hwang1
1Albert Einstein College of Medicine, Bronx, New York, USA
The assessment of abdominal fat by MRS vs. MRI on a cohort of subjects is reported. Both methods provide comparable quantitative measurements of abdominal fat depots. However, MRI is a better choice to measure abdominal fat as well as subcutaneous and intra-abdominal fat. Nevertheless, MRS on small voxel in subcutaneous fat detected fatty acid composition changes with diet in that a higher intake of fat caused increased proportional content of saturated fatty acid in adipose tissue triglycerides.
What Happens After Two Years of Lifestyle
Intervention? Changes in Different Adipose Tissue Compartments Assessed
by MRI and MRS
Jürgen Machann1, Claus Thamer2, Fabian Springer1, Norbert Stefan2, Hans-Ulrich Haring2, Claus D. Claussen3, Andreas Fritsche2, Fritz Schick1
1Section on Experimental Radiology, Tübingen, Germany; 2Department of Endocrinology, Metabolism, Clinical Chemistry, Nephrology and Angiology, Tübingen, Germany; 3Department of Diagnostic Radiology, Tübingen, Germany
Due to its increasing prevalence, overweight and obesity as well as the concomitant diseases as type 2 diabetes (T2DM) are a hot topic in our modern society. MR examinations were performed in a cohort of 130 subjects (3 examinations each) at increased risk for T2DM during a lifestyle intervention (LI) program of 2 years for quantification of different adipose tissue (AT) compartments and their changes after LI. Visceral AT and hepatic lipids showed the most prominent changes whereas subcutaneous AT was almost unchanged. Further factors influencing the success of LI – as genetic predispositions – are discussed.
Understanding Ethnic Differences in Body
Adiposity in the Newborn
Vimal Vasu1, Louise Thomas2, Chitranjan Yajnik3, Shalini Umranikar3, Peter McEwan1, Sabita Uthaya1, Jimmy Bell2, Neena Modi1
1Imperial College London, London, UK; 2Hammersmith Hospital, Imperial College London, London, UK; 3King Edward Memorial Hospital and Research Center, Pune, India
South Asians (SA), have higher prevalence of diabetes and insulin resistance and show ethnic differences in body composition. Here we investigate, using whole-body magnetic resonance imaging (MRI), whether such differences are apparent at birth. We compared body adiposity in 53 Caucasian and SA neonates and show that the latter have altered body fat distribution, although the overall content is the same.
| Liver and Muscle Lipid Stores and Their Association
with Abdominal Fat Distribution in Healthy Elderly Individuals
Alison Sleigh1, Francis Finucane2, David Savage1, Jessica Horton2, Lisa Purslow2, Sally Harding1, T A. Carpenter1, Nick Wareham2
1University of Cambridge, Cambridge, UK; 2Institute of Metabolic Science, Cambridge, UK
70 healthy elderly volunteers (aged 67-76 years) were recruited for measurements of abdominal fat distribution using MR imaging and IHL and IMCL using single voxel 1H-MR spectroscopy. Results suggest that IHL is closely related to measures of abdominal fat distribution and compartmentalisation. After adjusting for age and BMI, IHL was found to be more strongly associated with visceral and visceral/subcutaneous ratio, rather than subcutaneous fat. Our findings are consistent with studies in younger individuals, but have not been reported in an older cohort such as ours until now.
A Comparison of Hepatic Lipid and
Glycogen Levels in Type II Diabetics Using 1H and 13C MRS
Mary C. Stephenson1, Emily Leverton1, Eric Y. H. Khoo1, Simon M. Poucher2, Carsten Liess3, Andrew J. Lockton3, Lars Johansson4, 5, Jan W. Eriksson, 46, Peter Mansell1, Ian A. MacDonald1, Peter G. Morris1
1University of Nottingham, Nottingham, UK; 2AstraZeneca , Macclesfield, UK; 3AstraZeneca, Macclesfield, UK; 4AstraZeneca, Mölndal, Sweden; 5Uppsala University Hospital, Uppsala, Sweden; 6Sahlgrenska University Hospital, Gothenburg , Sweden
Metabolic disturbances in diabetes may include an increase in hepatic lipid concentration which has been suggested to contribute to the level of insulin resistance. The purpose of this study was to compare basal lipid and glycogen levels using 1H and 13C MRS both in type II diabetic and in healthy age and BMI matched subjects. Liver lipid levels were approximately 3-fold higher in the diabetic group, when compared with the healthy subjects which was not reflected in hepatic glycogen levels. Our results also suggest that the degree of diabetic control and level of obesity may affect liver lipid concentration
|11:30||871.||Abnormal Exercise Function in Adolescents with Type 2
Diabetes Correlates Negatively with Soleus Muscle IMCL as Measured by 1H
Mark Steven Brown1, Deb Singel1, Judith Regensteiner1, Jane Reusch1, Kristen Nadeau1
1University of Colorado Health Sciences Center, Aurora, Colorado , USA
Adults with type 2 diabetes (T2D) exhibit impaired maximal exercise capacity (VO2max). We explored whether VO2max is also reduced in adolescents with T2D, by performing measurements of muscle extramyocellular lipids (EMCL) and intracellular lipids (IMCL) using 1H MRS in the soleus and tibialis anterior muscles, as well as VO2max, blood flow, autonomic function, body composition, inflammatory markers, and insulin sensitivity, in lean, obese, and T2D adolescents. The results show VO2max/kg was significantly lower in T2D vs. obese vs. lean subjects, and that VO2max inversely correlates with IMCL, as well as with markers of insulin sensitivity, endothelial function, and inflammation.
Insulin-Stimulated Mitochondrial ATP
Synthesis is Impaired in Rat Muscle by Fat-Enriched Diet
Brittany Yerby1, Valerie Beaulieu, Richard Deacon, Jinsheng Liang, Jiaping Gao, Didier Laurent1
1Novartis Institutes for Biomedical Research, Inc, Cambridge, Massachusetts, USA
This study describes the inhibitory effects of increased lipid availability on insulin-stimulated ATP synthesis rates as measured in rat muscle by 31P saturation transfer. The euglycemic-hyperinsulinemic clamp approach used here not only improves sensitivity, but also mimics a physiological challenge that is relevant for pharmacological studies on anti-diabetic drugs aimed at improving mitochondrial function.
|Impact on Basal and Maximal ATP Turnover of
Structured Physical Activity Counselling in Type 2 Diabetes: A 31P MRS
Kieren Grant Hollingsworth1, Michael I. Trenell1, Ee Lin Lim1, Jean Gerrard1, Roy Taylor1
1Newcastle University, Newcastle Upon Tyne, UK
In type 2 diabetes (T2D), it is hypothesised that impaired mitochondrial function reduces the ability of muscle to metabolise fatty acids. Previous studies show that glucose control is improved by structured exercise counselling, but the mechanism of this improvement is unclear. We have measured both basal and maximal ATP turnover by 31P MRS before and after an eight-week physical activity intervention on 10 sedentary T2D patients and 10 controls matched for age, sex and physical activity. The counselling successfully achieved increased activity, weight loss and improvement in lipid oxidation, but neither measure of ATP demand changed due to the intervention.
Manganese Enhanced MRI Detects Pancreatic Beta Cell
Function in Vivo
Patrick Francis Antkowiak1, Sarah Ann Tersey, Raghavendra G. Mirmira, Frederick H. Epstein
1University of Virginia, Charlottesville, USA
In normal individuals, pancreatic beta cells release insulin into the bloodstream after an increase in blood glucose level. In Type 1 diabetes, beta cell mass and function are impaired. Manganese-enhanced MRI has been used previously to probe beta cell function in vitro; we aimed to evaluate its effectiveness in vivo in mice. Manganese-enhanced inversion recovery imaging showed an increased normalized pancreas signal in normal mice after glucose stimulation versus a saline control injection. No increase in signal intensity was observed after glucose stimulation versus saline control in diabetic mice.
Fuel Metabolism During Exercise in Eu- And
Hyperglycemia in Subjects with Type 1 Diabetes Mellitus
Michael Ith1, Stefan Jenni1, Sabin Allemann1, Christoph Oetliker1, Silvia Wuerth2, Luc Tappy3, Peter Diem1, Emanuel R. Christ1, Chris Boesch1, Christoph Stettler1
1University Bern, Bern, Switzerland; 2University Basel, Basel, Switzerland; 3University Lausanne, Lausanne, Switzerland
Little is known about the effect of blood glucose levels on muscle fuel metabolism during aerobic exercise in individuals with Type1 diabetes mellitus. The goal of the presented study therefore was to investigate muscular lipid and glycogen consumption during either eu- or hyperglycemic conditions during aerobic exercise. Two hours of cycling at an output power corresponding to 55-60% of VO2max revealed similar glycogen consumption, but higher IMCL consumption during euglycemic exercise condition coupled with a significantly lower RER. Therefore energy utilization of subjects with T1DM tends to rely on carbohydrate oxidation under hyperglycemia and shift to lipid oxidation during euglycemia.