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Physiological adaptation of the heart to pathological overloading
Federation Proceedings
|October 1, 1986
Summary
Chronic heart overload triggers rapid isomyosin shifts in rats, enhancing cardiac efficiency. However, humans show minimal isomyosin adaptation, suggesting species-specific responses to heart stress.
Area of Science:
- Cardiovascular Physiology
- Cellular Biology
- Biochemistry
Background:
- Chronic heart overload induces compensatory mechanisms like hypertrophy and isomyosin changes for increased efficiency.
- Adaptational strategies at the subcellular level in myocardial cells remain incompletely understood.
Purpose of the Study:
- To investigate adaptational changes in myocardial cells beyond hypertrophy in response to chronic heart overload.
- To compare the molecular adaptational responses, specifically isomyosin shifts, between rats and humans under chronic compensatory hypertrophy.
Main Methods:
- Experimental aortic stenosis in young rats to induce chronic heart overload.
- Analysis of human hearts with chronic compensatory hypertrophy.
- Double immunofluorescence labeling of isolated myocytes using anti-V1 and anti-V3 myosin antibodies.
- Visualization of microtubule patterns using immunofluorescence.
Main Results:
- A rapid shift from high-ATPase to low-ATPase isomyosins (2-3 days) was observed in rats following aortic stenosis.
- Cardiac myocytes exhibited a discernible microtubule network, though their role in adaptation is unclear.
- Humans with chronic compensatory hypertrophy displayed minimal to no significant changes in isomyosin profiles compared to rats.
Conclusions:
- The rat heart rapidly adapts to chronic overload via significant isomyosin shifts, enhancing contractile efficiency.
- Microtubule involvement in cardiac adaptation requires further investigation.
- Species-specific differences exist in the molecular adaptation of the heart to chronic overload, particularly concerning isomyosin expression.