Abstract
Changes in morphology and cytochromes content of the heart mitochondria (M) have been demonstrated with maturation in animal model systems. To determine if cytochrome c oxidase (CO) content and activity correlates with M development in the human heart we performed electron microscopic (EM) and biochemical studies of ventricular myocardium from samples obtained at autopsy in 6 patients (age range 6 days to 22 yrs, mean 6 yrs). None had evidence of cardiac pathology. Qualitative analysis of mitochondrion number, volume and fine structure was performed by EM of negatively stained, thin sections of fixed cardiac tissue. CO content was assessed by dithionite reduced minus ferricyanide oxidized spectra of isolated M and CO activity was determined by polarographic assay using saturating concentration of horse cytochrome c as substrate. An increase in CO content and activity was observed from the neonatal period (0.3nm heme a/mg protein and 140 nmO2/min/mg protein) to adulthood (1.0 nm heme a/mg protein and 1104 nmO2/min/mg protein). The number and structiral organization of M was also noted to increase with age mainly from the early neonatal period to infancy. Thus, in human heart development there is a continuing biogenesis of M after birth. Number and size of M increases as well as M with higher CO content and activity.
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Marin-Garcia, J., Kosaki, T. & Dockter, M. 119 CYTOCHROME c OXIDASE IN THE DEVELOPING HUMAN HEART. CORRELATION WITH MITOCHONDRIAL ULTRASTRUCTURE. Pediatr Res 19, 130 (1985). https://doi.org/10.1203/00006450-198504000-00149
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DOI: https://doi.org/10.1203/00006450-198504000-00149