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Deficiency of pyruvate dehydrogenase complex in tissues of an eight month old infant
H Hansikova1, J Zeman, P Klement
1Department of Pediatrics, Charles University, Prague, Czech Republic.
Insights
A study on an infant with failure to thrive revealed impaired pyruvate dehydrogenase complex (PDH) activity, particularly in muscle and liver tissues. This metabolic defect contributed to the infant's severe health issues and eventual death.
Area of Science:
- Biochemistry
- Pediatric Medicine
- Metabolic Disorders
Background:
- Investigated a case of intrauterine hypotrophia, failure to thrive, psychomotoric retardation, and cerebral atrophy in an infant.
- Examined metabolic pathways contributing to severe pediatric health conditions.
Observation:
- Infant presented with intermittent lactic acidosis, but a normal lactate/pyruvate ratio.
- Cytochrome c oxidase activity was within normal limits across multiple tissues.
- Pyruvate dehydrogenase complex (PDH) activity was reduced in muscle, heart, and liver mitochondria, but not in fibroblasts.
Findings:
- Confirmed decreased PDH activity in key metabolic tissues.
- Identified reduced E1 alpha subunit levels in skeletal muscle.
- Observed increased E1 alpha phosphorylation in liver mitochondria, suggesting regulatory dysfunction.
Implications:
- Highlights the critical role of pyruvate dehydrogenase complex activity in infant development.
- Suggests tissue-specific defects in PDH function can lead to severe metabolic disease.
- Underscores the importance of investigating PDH complex in unexplained failure to thrive and neurological impairment.
Abstract:
A metabolic investigation was carried out in an eight-month old infant with intrauterine hypotrophia, failure to thrive, psychomotoric retardation and cerebral atrophy, who died after respiratory infections. Blood analysis revealed intermittent lactic acidosis with normal lactate/pyruvate ratio. Activities of cytochrome c oxidase in skeletal muscle, heart, liver and fibroblasts were all in the reference range of controls. Activity of pyruvate dehydrogenase complex (PDH) was decreased in muscle homogenate, heart and liver mitochondria but was normal in cultured skin fibroblasts. Immunodetection of PDH subunits, and assay of El alpha phosphorylation showed in the patient decrease of E1 alpha in skeletal muscle, and enhanced level of E1 alpha phosphorylation in liver mitochondria.