Mice deleted for heart-type cytochrome c oxidase subunit 7a1 develop dilated cardiomyopathy.

Subunit 7a of mouse cytochrome c oxidase (Cox) displays a contractile muscle-specific isoform, Cox7a1, that is the major cardiac form. To gain insight into the role of this isoform, we have produced a new knockout mouse line that lacks Cox7a1. We show that homozygous and heterozygous Cox7a1 knockout mice, although viable, have reduced Cox activity and develop a dilated cardiomyopathy at 6 weeks of age.

Leptin's regulation of obesity-induced cardiac extracellular matrix remodeling.

Obesity-induced remodeling of cardiac extracellular matrix (ECM) leads to myocardial fibrosis and ultimately diastolic dysfunction. Leptin, an adipocyte hormone, is emerging as a novel mechanistic link between obesity and heart diseases. Despite the known essential role of leptin in hepatic and renal fibrosis, the in vivo effects of leptin on cardiac ECM remodeling remain unclear.