Aging in rats was associated with a reduction in normalized intramyocardial vessel volume and an increase in epicardial vessel volume, alongside increased LV fibrosis and mild LV dysfunction.
Cardiac micro-CT imaging demonstrates that aging in rats is associated with reduced intramyocardial vessel volume, increased epicardial vessel volume, LV fibrosis, and mild LV dysfunction.
Background— Alterations at the level of the coronary circulation with aging may play an important role in the evolution of age-associated changes in left ventricular (LV) fibrosis and function. However these age-associated changes in the coronary vasculature remain poorly defined primarily due to the lack of high resolution imaging technologies. The current study was designed to utilize cardiac micro–computed tomography (micro-CT) technology as a novel imaging strategy, to define the 3-dimensional coronary circulation in the young and aged heart and its relationship to LV fibrosis and function. Methods and Results— Young (2 months old; n=10) and aged (20 months old; n=10) Fischer rats underwent cardiac micro-CT imaging as well as echocardiography, blood pressure, and fibrosis analysis. Importantly, when indexed to LV mass, which increased with age, the total and intramyocardial vessel volumes were lower, whereas the epicardial vessel volume, with and without indexing to LV mass, was significantly higher in the aged hearts compared with the young hearts. Moreover, the aged hearts had a significantly lower percentage of intramyocardial vessel volume and a significantly higher percentage of epicardial vessel volume, when normalized to the total vessel volume, compared with the young hearts. Further, the aged hearts had significant LV fibrosis and mild LV dysfunction compared with the young hearts. Conclusions— This micro-CT imaging study reports the reduction in normalized intramyocardial vessel volume within the aged heart, in association with increased epicardial vessel volume, in the setting of increased LV fibrosis, and mild LV dysfunction.
Sangaralingham et al. (2012) studied Aging coronary vasculature (n=20). Aging vs. Young (2 months old) was evaluated on Coronary vessel volumes (total, intramyocardial, epicardial), LV fibrosis, and LV function. Aging in rats was associated with a reduction in normalized intramyocardial vessel volume and an increase in epicardial vessel volume, alongside increased LV fibrosis and mild LV dysfunction.