Cellular mechanisms of impaired cardiac energetics in patients with dilated cardiomyopathy: decrease in mitochondrial respiration and creatine kinase expression]

The mitochondrial functional characteristics were assessed in the biopsy specimens from patients with various Functional Classes dilated cardiomyopathy (DCMP). The assessment was made by using endomyocardial biopsy specimens weighing 2-4 mg which had been taken from 39 patients aged 19-64 years during coronary ventriculography and cardiac transplantation. The status of mitochondria and the efficiency of mitochondrial creatine kinase functioning were evaluated by recording the respiration of saponin-skinned muscular fibers. The maximum mitochondrial respiration rate calculated on a dry weight basis was not substantially different in all functional classes of DCMP, while the acceptor control index (Vmax/V0) and the level of creatine-activated respiration decreased with an increase in the functional class of DCMP. The findings show a good positive correlation between ejection fraction and creatine-stimulated respiration values and a linear negative correlation between this parameter and end-diastolic pressures. Thus, the respiratory parameters of mitochondria in the endomyocardial biopsy specimens may be used to assess the severity of cardias lesions.