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Enzymic analysis of cardiac biopsy material from patients with valvular heart-disease
Insights
Reduced myofibrillary calcium-dependent adenosine-triphosphatase (A.T.P.ase) activity in cardiac tissue correlates with poor left ventricular function in valvular heart disease patients. Increased cytosol lactate dehydrogenase activity was also observed.
Area of Science:
- Biochemistry
- Cardiology
- Molecular Biology
Background:
- Valvular heart disease can lead to impaired left ventricular function.
- Understanding the biochemical basis of this impairment is crucial for effective treatment.
Purpose of the Study:
- To investigate marker enzyme activities in subcellular organelles of cardiac tissue from patients with valvular heart disease.
- To correlate these enzyme activities with left ventricular function.
Main Methods:
- Endomyocardial biopsies were obtained from patients with valvular heart disease.
- Assayed marker enzyme activities of subcellular organelles.
- Correlated enzyme activities with left ventricular function using hemodynamic studies.
Main Results:
- Significantly reduced calcium-dependent adenosine-triphosphatase (A.T.P.ase) activity in myofibrils of patients with poor left ventricular function.
- Significantly increased lactate dehydrogenase activity (cytosol enzyme) in patients with poor left ventricular function.
- No significant differences in enzyme activities of sarcolemma, mitochondria, microsomes, or lysosomes between good and poor ventricular function groups.
Conclusions:
- Reduced myofibrillary calcium-dependent A.T.P.ase concentration is suggested as the biochemical basis for impaired ventricular function in valvular heart disease.
- Lactate dehydrogenase activity may serve as a potential indicator of cardiac dysfunction.
Abstract:
Cardiac tissue obtained by left-ventricular endomyocardial biopsy from patients with valvular heart-disease was assayed for marker enzyme activities of subcellular organelles and these were correlated with left ventricular function as assessed by haemodynamic studies. In patients with poor left ventricular function, calcium-dependent adenosine-triphosphatase (A.T.P.ase) activity, predominantly localised to the myofibrils, was strikingly reduced. Activity of lactate dehydrongenase, a cytosol enzyme, was significantly increased in tissue from patients with poor left ventricular function. The activity of enzymes associated with sarcolemma (5'-nucleotidase), mitochondria (glutamate dehydrogenase and monoamine oxidase), microsomes (neutral alpha-glucosidase), and lysosomes (acid phosphatase, N-acetyl-beta-glucosaminidase) was no different in patients with good or poor left ventricular function. It is suggested that reduced myofibrillary A.T.P.ase concentration is the biochemical basis for the impaired ventricular function.