What question did this study set out to answer?

To determine the changes in the rates of left ventricular myosin synthesis and degradation during the development of pressure-overload cardiac hypertrophy.

June 1, 1972Circulation ResearchOpen Access

Myosin Synthesis and Degradation during Development of Cardiac Hypertrophy in the Rabbit

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Why the study?

Does banding of the ascending aorta alter myosin synthesis and degradation during the development of cardiac hypertrophy in rabbits?

Population

58 rabbits weighing 2.7-3.2 kg

Comparison

Banding of the ascending aorta to induce cardiac… vs Sham operation

Design

Preclinical

Follow-up

Up to 16 days

Authors

EMEugene MorkinUniversity of Arizona SKS KimataHarvard University JSJohn J. SkillmanBrigham and Women's Hospital

Discussion

Member takes

Implication

Does not alter clinical practice; extends mechanistic understanding of hypertrophy in animal models while leaving human translation open.

Key Points

To determine the changes in the rates of left ventricular myosin synthesis and degradation during the development of pressure-overload cardiac hypertrophy.
Subjected 58 rabbits (2.7–3.2 kg) to 65% ascending aortic banding or sham surgery.
Administered 3H-lysine (0.5 mc/kg) to quantify incorporation into myosin across days 2–15 (N=26) and isotope clearance across days 3–16 (N=32).
Calculated daily degradation rate constants and evaluated turnover dynamics using computerized simulation modeling.
Aortic banding elevated left ventricular peak systolic pressure from 97 to 163 mm Hg and increased the ratio of left ventricular weight to body weight by approximately 16%.
Myosin synthesis rose above controls after day 2 and peaked at a 117% increase on day 10, alongside a 56% peak increase in total protein synthesis.
Computer modeling indicated that myosin degradation rates rose concurrently with synthesis, demonstrating that cardiac enlargement is primarily driven by accelerated protein production.

Structured PICO

Does banding of the ascending aorta alter myosin synthesis and degradation during the development of cardiac hypertrophy in rabbits?

Population

58 rabbits weighing 2.7-3.2 kg

Intervention

Banding of the ascending aorta (65% occlusion) to induce cardiac hypertrophy

Comparator

Sham operation

Outcome

Metabolism of left ventricular myosin (synthesis and degradation)surrogate

The increased myosin content observed during the development of cardiac hypertrophy is primarily driven by an increase in myosin synthesis rather than a decrease in degradation.

Cite This Study

Morkin et al. (1972) studied this question.

synapsesocial.com/papers/6a853a8cf9033a4f45d97bb2 https://doi.org/10.1161/01.res.30.6.690

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Myosin Synthesis and Degradation during Development of Cardiac Hypertrophy in the Rabbit

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Myosin Synthesis and Degradation during Development of Cardiac Hypertrophy in the Rabbit

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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