Open Access Original investigation

Cardiac lipid content is unresponsive to a physical activity training intervention in type 2 diabetic patients, despite improved ejection fraction

Vera B Schrauwen-Hinderling12*, Ruth CR Meex134, Matthijs KC Hesselink13, Tineke van de Weijer15, Tim Leiner267, Michael Schär89, Hildo J Lamb10, Joachim E Wildberger2, Jan FC Glatz116, Patrick Schrauwen15 and M Eline Kooi126

Author Affiliations

1 NUTRIM, School of Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands

2 Department of Radiology, Maastricht University Medical Center, Maastricht, The Netherlands

3 Department of Human Movement Sciences, Maastricht University Medical Center, Maastricht, The Netherlands

4 Biology of Lipid Metabolism Laboratory, Department of Physiology, Monash University, Clayton, Victoria, Australia

5 Department of Human Biology, Maastricht University Medical Center, Maastricht, The Netherlands

6 Cardiovascular Research Institute, CARIM, Maastricht University Medical Center, Maastricht, The Netherlands

7 Department of Radiology, Utrecht University Medical Center, Utrecht, The Netherlands

8 Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA

9 Philips Healthcare, Cleveland, Ohio, USA

10 Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands

11 Department of Molecular Genetics, Maastricht University Medical Center, Maastricht, The Netherlands

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Cardiovascular Diabetology 2011, 10:47  doi:10.1186/1475-2840-10-47

Published: 26 May 2011

Abstract

Background

Increased cardiac lipid content has been associated with diabetic cardiomyopathy. We recently showed that cardiac lipid content is reduced after 12 weeks of physical activity training in healthy overweight subjects. The beneficial effect of exercise training on cardiovascular risk is well established and the decrease in cardiac lipid content with exercise training in healthy overweight subjects was accompanied by improved ejection fraction. It is yet unclear whether diabetic patients respond similarly to physical activity training and whether a lowered lipid content in the heart is necessary for improvements in cardiac function. Here, we investigated whether exercise training is able to lower cardiac lipid content and improve cardiac function in type 2 diabetic patients.

Methods

Eleven overweight-to-obese male patients with type 2 diabetes mellitus (age: 58.4 ± 0.9 years, BMI: 29.9 ± 0.01 kg/m2) followed a 12-week training program (combination endurance/strength training, three sessions/week). Before and after training, maximal whole body oxygen uptake (VO2max) and insulin sensitivity (by hyperinsulinemic, euglycemic clamp) was determined. Systolic function was determined under resting conditions by CINE-MRI and cardiac lipid content in the septum of the heart by Proton Magnetic Resonance Spectroscopy.

Results

VO2max increased (from 27.1 ± 1.5 to 30.1 ± 1.6 ml/min/kg, p = 0.001) and insulin sensitivity improved upon training (insulin stimulated glucose disposal (delta Rd of glucose) improved from 5.8 ± 1.9 to 10.3 ± 2.0 μmol/kg/min, p = 0.02. Left-ventricular ejection fraction improved after training (from 50.5 ± 2.0 to 55.6 ± 1.5%, p = 0.01) as well as cardiac index and cardiac output. Unexpectedly, cardiac lipid content in the septum remained unchanged (from 0.80 ± 0.22% to 0.95 ± 0.21%, p = 0.15).

Conclusions

Twelve weeks of progressive endurance/strength training was effective in improving VO2max, insulin sensitivity and cardiac function in patients with type 2 diabetes mellitus. However, cardiac lipid content remained unchanged. These data suggest that a decrease in cardiac lipid content in type 2 diabetic patients is not a prerequisite for improvements in cardiac function.

Trial registration

ISRCTN: ISRCTN43780395

Keywords:
magnetic resonance spectroscopy; magnetic resonance imaging; ectopic fat; type 2 diabetes mellitus; exercise; cardiomyopathy; lipotoxicity