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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.

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.

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.

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.

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

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.

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.

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.

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.

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 VO_2max 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.