Mitochondrial gene expression and respiratory enzyme activities in cardiac diseases.
Respiratory enzyme activities and steady-state level of two mitochondrial-encoded transcripts were quantified in heart muscle biopsies from patients suffering various types of cardiomyopathies unrelated to mitochondrial primary disorders. We have found that although the mitochondrial DNA copy number and the concentration of COI and ND4 transcripts remain fairly constant, there is an important increase (up to 6-fold) in respiratory enzyme activities affecting to several oxidative phosphorylation complexes. Idiopathic dilated cardiomyopathy shows the greatest increase, followed by ischemic heart and ventricular hypertrophy due to aortic stenosis. The results suggest an energetic compensatory mechanism in the heart muscle, in the absence of mitochondrial proliferation or activation of mitochondrial gene expression.
Bornstein
B
B
Departamento de Bioquímica UAM, Instituto de Investigaciones Biomédicas CSIC, Facultad de Medicina, Universidad Autónoma de Madrid, Spain.
Huertas
R
R
Ochoa
P
P
Campos
Y
Y
Guillen
F
F
Garesse
R
R
Arenas
J
J
D004272:DNA, Mitochondrial / Q000235:genetics*; D004789:Enzyme Activation; D005260:Female; D015870:Gene Expression; D006331:Heart Diseases / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008929:Mitochondria, Heart / Q000201:enzymology / Q000235:genetics*; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D010085:Oxidative Phosphorylation
D004272:DNA, Mitochondrial; D009097:Multienzyme Complexes