Résumé :
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Facioscapulohumeral Muscular Dystrophy, Glucose Metabolism and Insulin Resistance A. Pakula, A. Mer, S. Schmidt, F.C. Luft, S. Spuler, M. Boschmann Franz-Volhard- Centrum fr Klinische Forschung, Charitiversitmedizin Berlin, Deutschland Hypothesis: Facioscapulohumeral muscular dystrophy (FSHD) is the third most common muscle dystrophic disease with an estimated incidence of 1:20.000. It is associated with a deletion of the long arm of chromosome 4, is autosomal inherited and usually begins in early adulthood. Symptoms are facial weakness around the mouth and eyes, shoulder girdle and arm with the progression to the leg, back and trunk. The pathophysiological consequences of the chromosomal defect are unclear. Until today, there is no effective treatment. We wanted to test the hypothesis that FSHD patients show impaired glucose uptake and partial insulin resistance, especially in affected muscles. Methods: Insulin sensitivity was tested in 10 FSHD patients and in 10 normal-weight , healthy volunteers by an oral glucose tolerance test (oGTT). Blood samples were analyzed for [glucose], [insulin] and [free fatty acids, FFA]. Basal and postprandial energy metabolism was measured by calorimetry and local tissue metabolism in abdominal-subcutaneous adipose tissue and skeletal muscle (vastus lateralis) by microdialaysis. Dialysates were analyzed for [glucose], [lactate], [pyruvate] and [glycerol] as indicators for glucose metabolism and lipolysis. Tissue perfusion was assessed by the ethanol dilution technique.Results: Compared to healthy controls, FSHD patients showed a marginal impaired glucose tolerance and postprandial hyperinsulinaemia during oGTT. Basal FFA and ketone bodies were also higher in FSHD patients. Skeletal muscle showed a reduced blood flow and glucose supply, and an impaired basal and postprandial glucose utilization. Baseline lipolysis was also significantly higher in FSHD patients vs. healthy control, but decreased to the same level as in healthy controls during oGTT. Systemic lipid oxidation showed no differences between FSHD patients and healthy controls.Conclusions: FSHD patients demonstrate an impaired glucose utilization in skeletal muscles which is possibly compensated by an increased local lipolysis and lipid oxidation.
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