We studied cardiac function in young and old, wild-type (WT), and longer-living Little mice using cardiac flow velocities, echocardiographic measurements, and left ventricular (LV) pressure (P) to determine if enhanced reserves were in part responsible for longevity in these mice. Resting/baseline cardiac function, as measured by velocities, LV dimensions, +dP/dt max, and -dP/dtmax, was significantly lower in young Little mice versus young WT mice. Fractional shortening (FS) increased significantly, and neither +dP/dtmax nor -dP/dtmax declined with age in Little mice. In contrast, old WT mice had no change in FS but had significantly lower +dP/dtmax and -dP/dtmax versus young WT mice. Significant decreases were observed in the velocity indices of old Little mice versus old WT mice, but other parameters were unchanged. The magnitude of dobutamine stress response remained unchanged with age in Little mice, while that in WT mice decreased. These data suggest that while resting cardiac function in Little mice versus WT mice is lower at young age, it is relatively unaltered with aging. Additionally, cardiac function in response to stress was maintained with age in Little mice but not in their WT counterparts. Thus, some mouse models of increased longevity may not be associated with enhanced reserves.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journals of Gerontology - Series A Biological Sciences and Medical Sciences|
|State||Published - Dec 2007|
ASJC Scopus subject areas
- Geriatrics and Gerontology