Blunted cardiac beta-adrenergic response as an early indication of cardiac dysfunction in Duchenne muscular dystrophy.

ABSTRACT:

Aims

To determine whether altered beta-adrenergic responses contribute to early cardiac dysfunction in mdx (X-linked muscular dystrophy) mice, an animal model for human Duchenne muscular dystrophy.

Methods and results

Replacement fibrosis in mdx hearts gradually increased with age, suggesting a gradual loss of cardiomyocytes. Echocardiography and intra-left ventricular haemodynamic measurements detected baseline cardiac dysfunction in mdx mice at ≥8 months. However, a reduction of cardiac beta-adrenergic response to isoproterenol (ISO) was already present in mdx mice at 4 months. Ventricular myocytes (VMs) isolated from 4- and 8-month-old mdx mice had greater baseline contractile function {fractional shortening, [Ca(2+)]i, and sarcoplasmic reticulum (SR) Ca(2+) content} and

SUBMITTER: Li Y 

PROVIDER: S-EPMC4133593 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature