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Developmental changes in left and right ventricular diastolic filling patterns in mice
Yu-Qing Zhou1, F Stuart Foster, Robert Parkes
1Samuel Lunenfeld Research Institute, Mount Sinai Hospital, and Department of Physiology, University of Toronto, Ontario, Canada M5G 1X5.
Summary
Mice show significant changes in heart diastolic function after birth, with maturation occurring around three weeks post-delivery. This study tracked ventricular filling patterns from embryonic stages to adulthood.
Area of Science:
- Cardiovascular Physiology
- Developmental Biology
- Echocardiography
Background:
- Diastolic filling patterns are crucial for cardiac function and can change significantly during development.
- Understanding these developmental changes in animal models provides insights into human cardiovascular maturation.
Purpose of the Study:
- To characterize the developmental trajectory of left and right ventricular diastolic filling patterns in mice.
- To identify the age at which diastolic function matures postnatally.
Main Methods:
- Noninvasive echocardiography with 20-MHz pulsed Doppler was used to assess blood flow velocities in mitral and tricuspid orifices.
- Measurements were taken in embryonic (E14.5, E17.5) and postnatal mice (1-7 days, 1-4 weeks, 4-12 weeks).
- Key parameters quantified included peak E/A ratio and peak E/total TVI ratio.
Main Results:
- Both ventricles exhibited similar diastolic filling patterns in embryos.
- Postnatally, mitral peak E/A ratio increased significantly, exceeding 1 by day 3-5 and stabilizing around 3 weeks.
- Tricuspid peak E/A ratio showed a smaller increase but also stabilized by 3 weeks, with age-related changes driven by increased peak E velocity.
Conclusions:
- Ventricular diastolic function in mice matures approximately 3 weeks after birth.
- This maturation is likely linked to the development of ventricular recoil and relaxation mechanisms.
- The study provides a detailed timeline of diastolic function development in a murine model.