The effects of estrogen deficiency and aging on myocardial deformation and motion in normotensive female rats

Abstract

Objective: 

Estrogen deficiency is associated with left ventricular (LV) dysfunction in postmenopausal women and ovariectomized rats. Whether the relationship between estrogen deficiency and LV dysfunction is independent of cardiovascular disease (CVD) risk factors remains uncertain. This study assessed the effects of short-term and long-term estrogen deficiency on cardiac structure and function using conventional and speckle tracking echocardiography, independent of traditional CVD risk factors.

Methods: 

Female Sprague-Dawley rats were divided into short-term (6 wks) ovariectomized (n = 9), short-term sham-operated (n = 10), long-term (6 mo) ovariectomized (n = 8), and long-term sham-operated (n = 9) groups. Cardiac geometry, systolic and diastolic function, and myocardial deformation and motion were measured using echocardiography.

Results: 

Ovariectomy had no effect on conventional echocardiography measures of cardiac structure or function. Compared with short-term, long-term groups had reduced LV internal diameter (false discovery rate [FDR] adjusted P = 0.05) and impaired relaxation (e’; FDR adjusted P = 0.0005) independent of body mass and blood pressure (BP). Global longitudinal strain was impaired in ovariectomized compared with sham-operated rats (FDR adjusted P = 0.05), but not after adjusting for body mass and BP (FDR adjusted P = 0.16). Global longitudinal strain (FDR adjusted P = 0.05), strain rate (FDR adjusted P = 0.002), and velocity (FDR adjusted P = 0.04) were impaired in long-term compared with short-term groups. Global longitudinal strain rate remained impaired after adjustments for body mass and BP (FDR adjusted P = 0.02).

Conclusions: 

Estrogen deficiency does not independently cause cardiac remodeling, LV dysfunction, or impaired myocardial deformation. Traditional CVD risk factors accompanying estrogen deficiency may account for cardiac remodeling and dysfunction observed in postmenopausal women.