CELLULAR MECHANISMS OF IMPAIRED CARDIAC ENERGETICS IN PATIENTS WITH DILATED CARDIOMYOPATHY - A 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 (V(max)/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.