title: Cardiac lipid content is unresponsive to a physical activity training intervention in type 2 diabetic patients, despite improved ejection fraction.
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.
  
  
  BACKGROUND
  ISRCTN: ISRCTN43780395.
authors: NUTRIM, School of Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands. v.schrauwen@maastrichtuniversity.nl
authors: Vera B
authors: VB
authors: Schrauwen-Hinderling
authors: Ruth C R
authors: RC
authors: Meex
authors: Matthijs K C
authors: MK
authors: Hesselink
authors: Tineke
authors: T
authors: van de Weijer
authors: Tim
authors: T
authors: Leiner
authors: Michael
authors: M
authors: Schär
authors: Hildo J
authors: HJ
authors: Lamb
authors: Joachim E
authors: JE
authors: Wildberger
authors: Jan F C
authors: JF
authors: Glatz
authors: Patrick
authors: P
authors: Schrauwen
authors: M Eline
authors: ME
authors: Kooi
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