Echocardiographic Characterization of Postnatal Development in Mice with Reduced Arterial Elasticity

Decreased expression of elastin results in smaller, less compliant arteries, and high blood pressure. In mice, these differences become more significant with postnatal development. It is known that arterial size and compliance directly affect cardiac function, but the temporal changes in cardiac function have not been investigated in elastin insufficient mice. The aim of this study is to correlate changes in arterial size and compliance with cardiac function in wildtype (WT) and elastin haploinsufficient (Eln^+/-) mice from birth to adulthood. Ultrasound scans were performed at the ages of 3, 7, 14, 21, 30, 60, and 90 days on male and female WT and Eln^+/- mice. 2-D ultrasound and pulse wave Doppler images were used to measure the dimensions and function of the left ventricle (LV), ascending aorta, and carotid arteries. Eln^+/- arteries are smaller and less compliant at most ages, with significant differences from WT as early as 3 days old. Surprisingly, there are no correlations (R² < 0.2) between arterial size and compliance with measures of LV hypertrophy or systolic function. There are weak correlations (0.2 < R² < 0.5) between arterial size and compliance with measures of LV diastolic function. Eln^+/- mice have similar cardiac function to WT throughout postnatal development, demonstrating the remarkable ability of the developing cardiovascular system to adapt to mechanical and hemodynamic changes. Correlations between arterial size and compliance with diastolic function show that these measures may be useful indicators of early diastolic dysfunction.