Improved exercise tolerance after enzyme replacement therapy in Pompe disease.
OBJECTIVE
Enzyme replacement therapy (ERT) has recently became available for Pompe disease. Data on the effects of ERT on physiological variables related to exercise tolerance have never been published.


METHODS
Pulmonary gas exchange, cardiac output (by impedance cardiography), and vastus lateralis muscle O₂ extraction (by near-infrared spectroscopy) were determined during cycle ergometer exercise in a 50-yr-old patient before and after 1, 12, and 24 months of ERT.


RESULTS
At the same constant-workload submaximal exercise, RPE, R, pulmonary ventilation, and HR were lower during ERT versus before, suggesting an increased exercise tolerance. Peak oxygen uptake (V˙O2peak) increased by ~35% from before (0.64 L·min⁻¹ or 11.4 mL·kg·min⁻¹) to 1 month (0.88 L·min⁻¹ or 15.7 mL·kg·min⁻¹) of treatment and did not significantly change thereafter. Also, peak cardiac output significantly increased during ERT, whereas peak skeletal muscle fractional O₂ extraction was unchanged compared with before.


CONCLUSIONS
Improvements of peak exercise capacity and exercise tolerance at submaximal workloads were observed in a patient with Pompe disease after 1 month of ERT, with no further changes during the ensuing treatment period (up to 24 months).
Institute of Bioimaging and Molecular Physiology, CNR, Segrate, Milan, Italy. mauro.marzorati@ibfm.cnr.it
Mauro
M
Marzorati
Simone
S
Porcelli
Barbara
B
Reggiori
Lucia
L
Morandi
Bruno
B
Grassi
D002302:Cardiac Output / Q000502:physiology; D056947:Enzyme Replacement Therapy; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006009:Glycogen Storage Disease Type II / Q000188:drug therapy* / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D019265:Spectroscopy, Near-Infrared