Activities of respiratory chain complexes and pyruvate dehydrogenase in isolated muscle mitochondria in premature neonates

• Published in: Early human development Vol. 84; no. 4; pp. 269 - 276
• Main Authors: Honzik, T., Wenchich, L., Böhm, M., Hansikova, H., Pejznochova, M., Zapadlo, M., Plavka, R., Zeman, J.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier Ireland Ltd 01.04.2008; New York,NY Elsevier; Amsterdam
• Subjects: Adolescent; Advanced Basic Science; Aging - metabolism; Biological and medical sciences; Body Temperature - physiology; Child; Child, Preschool; Citrate (si)-Synthase - metabolism; Electron Transport - physiology; Electron Transport Complex III - metabolism; Electron Transport Complex IV - metabolism; Embryology: invertebrates and vertebrates. Teratology; Female; Follow-Up Studies; Fundamental and applied biological sciences. Psychology; Humans; Infant; Infant, Newborn; Infant, Premature - metabolism; Infant, Premature - physiology; Male; Mitochondria; Mitochondria, Muscle - enzymology; Muscle, Skeletal - cytology; Muscle, Skeletal - enzymology; Muscle, Skeletal - physiology; Neonatal and Perinatal Medicine; Premature neonates; Pyruvate dehydrogenase; Pyruvate Dehydrogenase Complex - metabolism; Respiratory chain complexes; Pyruvate dehydrogenase; Mitochondria; Premature neonates; Respiratory chain complexes; Human; Premature; Respiratory chain; Respirator chain complexes; Pyruvate; Striated muscle
• ISSN: 0378-3782; 1872-6232
• DOI: 10.1016/j.earlhumdev.2006.07.008

Most diseases in premature neonates are secondary to immaturity of various organ systems. Also the inadequate capacity of mitochondrial energy production may play an important role in the neonatal morbidity. The activities and amount of respiratory chain (RC) complexes, pyruvate dehydrogenase (PDH) and citrate synthase (CS) were analysed in isolated muscle mitochondria obtained at autopsy in 19 premature neonates using spectrophotometric and radioenzymatic methods and blue-native electrophoresis and Western blotting. Two groups of children recommended for muscle biopsy at the age of 0.5–2 and 3–18 years served as controls. In premature neonates, the activities of RC complexes III, IV, PDH and CS were markedly lower in comparison with older children. On the contrary, the activity of complex I was higher in premature neonates than in older children. The ratios between RC complexes I, II and III and CS were significantly higher in premature neonates in comparison with older children. In addition, the protein amount of RC complexes and PDH subunits were lower in premature neonates in comparison with older children. The results of our study document the age-dependent differences in activities of PDH and respiratory chain complexes in early childhood. Lower functional capacity of mitochondrial energy-providing system in critically ill neonates may be explained by combination of various factors including the delay in maturation of PDH and respiratory chain complexes in very premature neonates and increased degradation of mitochondrial proteins in connection with sepsis, tissue hypoperfusion or hypoxemia.