Heart failure-induced diaphragm myopathy.

Background: Intracellular signaling pathways involved in skeletal myosin heavy chain (MyHC) isoform alterations during heart failure (HF) are not completely understood. We tested the hypothesis that diaphragm expression of mitogen-activated protein kinases (MAPK) and myogenic regulatory factors is changed in rats with myocardial infarction (MI) induced HF.

Methods: Six months after MI rats were subjected to transthoracic echocardiography.

Myostatin and follistatin expression in skeletal muscles of rats with chronic heart failure.

Skeletal muscle abnormalities can contribute to decreased exercise capacity in heart failure. Although muscle atrophy is a common alteration in heart failure, the mechanisms responsible for muscle mass reduction are not clear. Myostatin, a member of TGF-beta family (transforming growth factor), regulates muscle growth and mass.