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Coordinated changes in contractility, energetics, and isomyosins after aortic stenosis
The American Journal of Physiology
|February 1, 1987
Summary
Ascending aorta stenosis in young rats rapidly induced significant cardiac hypertrophy and impaired myocardial performance within 8-10 days. Key changes in contractility and isomyosin patterns occurred early, with minimal further alterations observed later.
Area of Science:
- Cardiovascular Physiology
- Cardiac Remodeling
- Biochemistry
Background:
- Cardiac hypertrophy is a complex adaptation to increased workload.
- Understanding early molecular and mechanical changes is crucial for therapeutic targets.
Purpose of the Study:
- To investigate early alterations in myocardial mechanics and energetics following induced cardiac hypertrophy.
- To determine the time course of changes in isomyosin patterns during cardiac remodeling.
Main Methods:
- Cardiac hypertrophy induced via ascending aorta stenosis in young rats.
- Mechanical and energetic properties assessed in left ventricular papillary muscles.
- Isomyosin V1 and V3 patterns determined using biochemical assays.
Main Results:
- Significant left ventricular hypertrophy (53%) observed within 8-10 days.
- Reduced maximum unloaded shortening velocity (Vmax) and peak power output (Emax).
- Shift in isomyosin profile from V1 to V3, indicating altered contractility.
Conclusions:
- Early stages of cardiac hypertrophy (8-10 days) drive the most significant functional and biochemical changes.
- Myocardial performance is markedly impaired early in the hypertrophic process.
- Isomyosin shifts reflect adaptive or maladaptive responses to sustained cardiac overload.