Abstract 1956: Age-associated Changes In Left Ventricular Contractility And Ventricular-vascular Stiffness In Apolipoprotein E-deficient Mice
Objectives. To assess left ventricular contractile function and characteristics in the apolipoprotein E-deficient mouse model of severe atherosclerosis.
Methods. We studied cardiac performance in 24- and 60-weeks-old ApoE−/− mice and age-matched wild type (WT) mice, using a miniature pressure-volume (PV) conductance catheter. Load-independent contractility was assessed using preload recruitable stroke work (PRSW) and preload-corrected dP/dtmax (dP/dtmax/Ved).
Results (Table⇓). The two genotypes exhibited comparable contractile parameters at 24 weeks. Contracility (PRSW and dP/dtmax/Ved) of WT mice at 60 weeks was lower than at 24 weeks, as was arterial (Ea) and left ventricular end-systolic (Ees) elastance. In 60-week-old ApoE−/− mice, Ea and Ees were less reduced than in WT. End-diastolic left ventricular stiffness (EDPVR) increased with age in ApoE−/− mice. This was accompanied by a higher heart to body weight ratio and a reduced end-diastolic volume (Ved) indicating the presence of concentric hypertrophy in these mice. Load-independent contractility parameters decreased less in ApoE−/− than in WT, which can be explained by the left ventricular hypertrophy.
Conclusions. Our findings indicate that contractility is impaired at old age. In old ApoE−/− mice, exhibiting extensive atherosclerosis, ventricular-vascular stiffness is higher than in WT, end-diastolic left ventricular stiffness is increased, and concentric left ventricular hypertrophy develops.