Age-related divergent remodeling of the cardiac extracellular matrix in heart failure: Collagen accumulation in the young and loss in the aged

► Extracellular matrix remodeling in an aged HF animal model remains unexplored. ► Gross functional and morphological LV remodeling is greatest in aged HF sheep. ► Collagen content is increased in young HF but decreased in aged HF. ► MMP activity and collagen fibrillogenesis increases in both young HF and aged HF. ► TIMP protein levels are diminished only in aged HF hearts.