title: Blocked muscle fat oxidation during exercise in neutral lipid storage disease.
abstract: OBJECTIVE
  To determine whether impaired exercise capacity in neutral lipid storage disease with myopathy is solely caused by muscle weakness or whether a defect in energy metabolism (blocked fat oxidation) may also play a role.
  
  
  METHODS
  We studied a 37-year-old woman with neutral lipid storage disease with myopathy, who cycled while lipid oxidation was assessed using U-(13)C palmitate tracer dilution technique. The effect of a glucose infusion during exercise was also studied.
  
  
  METHODS
  Neuromuscular research unit.
  
  
  RESULTS
  The exercise-induced increase in fat oxidation was virtually abolished in the patient. Treatment with intravenous glucose infusion improved maximal oxygen uptake from 23 to 27 mL × kg(-1) × min(-1), and maximal workload from 75 to 100 W.
  
  
  CONCLUSIONS
  These results demonstrate that in addition to fixed weakness, neutral lipid storage disease with myopathy is also characterized by a profound block in fat oxidation, which limits exercise tolerance.
authors.affiliation: Centre de Référence de Pathologie Neuromusculaire Paris-Est, Bâtiment Babinski, Groupe Hospitalier Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75651 Paris CEDEX 13, France. pascal.laforet@psl.aphp.fr
authors.forename: Pascal
authors.initials: P
authors.lastname: Laforêt
authors.forename: Mette
authors.initials: M
authors.lastname: Ørngreen
authors.forename: Nicolai
authors.initials: N
authors.lastname: Preisler
authors.forename: Grete
authors.initials: G
authors.lastname: Andersen
authors.forename: John
authors.initials: J
authors.lastname: Vissing
mesh_terms: D000328:Adult; D001786:Blood Glucose; D002247:Carbon Isotopes / Q000097:blood / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism; D006339:Heart Rate; D006801:Humans; D016113:Ichthyosiform Erythroderma, Congenital / Q000473:pathology / Q000534:rehabilitation*; D007320:Inspiratory Capacity; D050356:Lipid Metabolism; D008052:Lipid Metabolism, Inborn Errors / Q000473:pathology / Q000534:rehabilitation*; D009135:Muscular Diseases / Q000150:complications / Q000473:pathology / Q000534:rehabilitation*; D010084:Oxidation-Reduction; D010168:Palmitates / Q000097:blood / Q000378:metabolism; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D002247:Carbon Isotopes; D005227:Fatty Acids; D010168:Palmitates; D005947:Glucose