Assessing metabolic profiles in human myoblasts from patients with late-onset Pompe disease.

BACKGROUND: Pompe disease is a neuromuscular disease caused by a deficiency of lysosomal acid alpha-glucosidase (GAA) which degrades glycogen, resulting in progressive accumulation of lysosomal glycogen, lysosomal swelling and rupture. In addition, mitochondrial abnormalities have been frequently observed in muscle biopsy specimens of Pompe patients. Enzyme replacement therapy (ERT) using alglucosidase alfa, a recombinant human GAA, is so far the only available therapy. We evaluated glycolysis and basal respiration in primary human myoblasts from patients with Pompe disease and in mouse myoblasts from GAA knockout mice before and after alglucosidase alfa treatment.
METHODS: We tested patient-derived primary human myoblasts and immortalized GAA-/- mouse myoblasts for GAA activity, glycolytic activity, and mitochondrial respiration before and after alglucosidase alfa treatment using enzyme activity assays and SeaHorse measurements.
RESULTS: A significant reduction in glycolysis (30%) and in mitochondrial respiration (50%) was observed in both, human and mouse GAA-deficient myoblasts. Treatment with alglucosidase alfa resulted in partial recovery of both metabolic pathways with some variability in human myoblasts.
CONCLUSIONS: Future assessments of treatment efficacy should include screening for the metabolic effects on both glycolysis and mitochondrial respiration in order to obtain a better read-out of the cellular energy metabolism.