Pyruvate therapy for mitochondrial DNA depletion syndrome

Background: Mitochondrial DNA depletion syndromes are a group of heterogeneous autosomal recessive disorders associated with a severe reduction in mitochondrial DNA in the affected tissues. Sodium pyruvate has been reported to have a therapeutic effect in mitochondrial diseases. Methods: We analyzed the effects of 0.5 g/kg of sodium pyruvate administered through a nasogastric tube in a one-year-old patient with myopathic mitochondrial DNA depletion syndrome. To evaluate the improvement, we used the Newcastle Paediatric Mitochondrial Disease Scale (NPMDS) and manual muscle testing. As the improvement of motor functions in this severely disabled infant could not be comprehensively detected by NPMDS, we also observed the infant's ability to perform several tasks such as pouting, winking, and number of times she could tap a toy xylophone with a stick. Blood lactate and pyruvate levels were also monitored. Results: After one month's treatment, the NPMDS score in section IV, the domain for the quality of life, improved from 17 to 13. The infant became capable of raising her forearm, lower leg and wrist against gravity. The maximum number of times she could repeat each task increased and the movements became brisker and stronger. No significant change of the blood lactate level or lactate-to-pyruvate ratio, both of which were mildly increased at the initiation of the therapy, was observed despite the clinical improvement. Conclusion: Sodium pyruvate administered at 0.5 g/kg improved the muscle strength and the NPMDS score of an infant with myopathic mitochondrial DNA depletion syndrome. General significance: Sodium pyruvate may be effective for ameliorating the clinical manifestations of mitochondrial diseases. This article is part of a Special Issue entitled: Biochemistry of Mitochondria. (C) 2011 Elsevier B.V. All rights reserved.