Impairment of the exercise-induced increase in muscle perfusion in McArdle's disease.
In McArdle's disease (myophosphorylase deficiency) exercise intolerance is generally attributed to a lack of glycogenolysis, which decreases energy production during exercise. Magnetic resonance imaging data have recently suggested an impairment of the increase in muscle perfusion during exercise in these patients. We have tested this hypothesis by direct measurement of local muscle perfusion increase. Increase in muscle perfusion was assessed by positron emission tomography with oxygen-15 labelled water in five patients with McArdle's disease and five age- and sex-matched healthy volunteers. Radioactivity was measured in both forearms before and after exercise of the right forearm. The exercise intensity was biochemically assessed by in vivo phosphorus-31 magnetic resonance spectroscopy. The estimated increase in muscle perfusion with exercise was 5.7+/-5.5-fold in the patients (range 1.5-12.8) and 22.3+/-12.0-fold in the healthy subjects (range 10.1-37) (P=0.022). The results show a significant impairment of increase in muscle perfusion with exercise in McArdle's disease. Thus patients may suffer not only from a direct lack of glycogenolysis but also from indirectly impaired vasodilation.
Jehenson
P
P
Service Hospitalier Frédéric Joliot, Commissariat à l'Energie Atomique, 4 place du Général Leclerc, F-91406 Orsay, France.
Leroy-Willig
A
A
de Kerviler
E
E
Merlet
P
P
Duboc
D
D
Syrota
A
A
D000328:Adult; D005260:Female; D005542:Forearm; D006012:Glycogen Storage Disease Type V / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D005082:Physical Exertion; D014055:Tomography, Emission-Computed
D010725:Phosphocreatine