Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 52, Issue 6 B285-B290, Copyright © 1997 by The Gerontological Society of America
The age-associated alterations in late diastolic function in mice are improved by caloric restriction
GE Taffet, TT Pham and CJ Hartley
Section of Cardiovascular Sciences, Baylor College of Medicine, Houston, USA.
Caloric restriction reduces the magnitude of many age-related changes in
rodents. Cardiac function is altered with senescence in mice, rats, and
healthy humans. We examined the effects of life-long caloric restriction on
diastolic and systolic cardiac function in situ using Doppler techniques in
ad libitum-fed 30- to 32-month-old (AL) and calorically restricted (CR) 32-
to 35-month-old female B6D2-F1 hybrid mice. The heart weight to body weight
ratio was similar in AL (5.74 +/- .24 mg/g) and CR (5.68 +/- .20 mg/g)
mice. Two systolic functional parameters known to decrease with age in both
humans and mice, peak aortic velocity and aortic acceleration, were
unchanged by CR compared to AL. In contrast, diastolic function was altered
by caloric restriction. Although left ventricular peak early filling
velocity (E) was not different between CR and AL, peak atrial filling
velocity (A) was 50% lower in CR compared to AL (p < .001). The ratio of
early diastolic filling to atrial filling (E/A ratio) was 64% higher in the
CR (2.74 +/- .31) than the AL (1.55 +/- .07; p = .004). The fraction of
ventricular filling due to atrial systole, the atrial filling fraction, was
also reduced in CR (.21 +/- .04) compared to AL (.36 +/- .02; p = .007).
These changes occurred in CR without alteration in E deceleration time,
which is consistent with improved diastolic function in CR. Through
mechanisms that remain unknown, lifelong caloric restriction may prevent
the age-related impairments in late diastolic function but does not alter
the impairments in systolic or early diastolic cardiac function.
