April 1, 1994Circulation Research126 citations
View Full PaperAlpha-skeletal actin is associated with increased contractility in the mouse heart.
Structured PICO
Does overexpression of alpha-skeletal actin increase cardiac contractility in a murine model?
P
Population
BALB/c mice (n=15) using the isolated perfused work-performing murine heart model
I
Intervention
Overexpression of alpha-skeletal actin isoform
O
Outcome
Myocardial contractility (maximum rate of contraction [+dP/dt], time to peak pressure, relaxation [-dP/dt], and time to half relaxation of left intraventricular pressure)surrogate
In a murine model, increased expression of alpha-skeletal actin is significantly correlated with enhanced cardiac contractile function.
Abstract
BALB/c mice express abnormally high levels of alpha-skeletal actin in the heart, which may be related to a duplication in the promoter of the alpha-cardiac actin gene. To evaluate the effects of overexpression of the alpha-skeletal actin isoform on cardiac contractile function, we studied these mice using the isolated perfused work-performing murine heart model and measured actin isoform expression in the same hearts. We quantified myocardial contractility from the maximum rate of contraction (+dP/dt) and time to peak pressure and relaxation from -dP/dt and time to half relaxation of left intraventricular pressure. Dot blots of total RNA hybridized against oligonucleotide sequences specific for either alpha-skeletal or alpha-cardiac actin mRNA showed that increased levels of alpha-skeletal actin RNA correlated significantly with increased contractility of hearts from the BALB/c mice (r = .80, n = 15, P < .001). The present study demonstrates a significant functional correlation between alpha-actin isoform content and cardiac contractile function and also that alpha-skeletal actin may promote an increased contractile function in the heart compared with alpha-cardiac actin.