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Biventricular Assessment of Cardiac Function and Pressure-Volume Loops by Closed-Chest Catheterization in Mice
Published on: June 15, 2020
Passive ventricular mechanics in tight-skin mice
J H Omens1, H A Rockman, J W Covell
1Department of Medicine, University of California at San Diego, La Jolla 92093.
The American Journal of Physiology
|March 1, 1994
Summary
The tight-skin (TSk) mouse model exhibits increased cardiac collagen and altered stress-free state. However, these changes did not impact the passive pressure-volume relationship of the left ventricle.
Area of Science:
- Cardiovascular Physiology
- Biomechanical Engineering
- Extracellular Matrix Research
Background:
- Changes in extracellular matrix composition, particularly collagen, are implicated in altered ventricular mechanics.
- The precise relationship between myocardial collagen content, residual stress, and passive ventricular compliance remains incompletely understood.
- The tight-skin (TSk) mouse model presents a unique genetic mutation leading to increased cardiac collagen, making it a valuable model for studying these relationships.
Purpose of the Study:
- To investigate the impact of increased myocardial collagen and altered residual stress on passive ventricular mechanics in the tight-skin (TSk) mouse.
- To determine if the TSk mouse model exhibits changes in left ventricular pressure-volume relationships and its stress-free state.
- To correlate histological findings of collagen distribution with biomechanical measurements.
Main Methods:
- Passive mechanical properties of arrested left ventricles were assessed in TSk mice and control littermates.
- Pressure-volume relationships were determined to evaluate ventricular compliance.
- The stress-free state was quantified using the "opening angle" of an equatorial ring with a radial cut.
- Histological analysis quantified transmural and superficial epicardial collagen content.
Main Results:
- TSk mice displayed a significantly smaller opening angle (indicating reduced residual stress) compared to controls (7° vs. 21°).
- No significant differences were observed in the passive pressure-volume curves between TSk mice and controls.
- Histological analysis confirmed increased collagen area fraction uniformly across the ventricular wall and a thicker superficial epicardial collagen layer in TSk mice.
Conclusions:
- Increased myocardial collagen and a reduced opening angle (decreased residual stress) in TSk mice do not alter passive left ventricular pressure-volume relationships.
- The thicker epicardial collagen layer may contribute to the observed decrease in residual stress.
- This study suggests that while collagen content and residual stress are affected, passive ventricular compliance remains unchanged in this model.
