Role of osteopontin in heart failure associated with aging.

Cardiovascular disease is one of the leading causes of death in the elderly. Much of the morbidity and mortality in the elderly is attributable to acute ischemic events leading to myocardial infarction (MI) and death of cardiac myocytes. Evidence has been provided that aging associated with adverse remodeling post MI as demonstrated by less effective myocardial repair, greater infarct expansion, and septal hypertrophy. Expression of osteopontin (OPN) increases in the heart post MI. Transgenic mice studies suggest that increased expression of OPN plays a protective role in post-MI LV remodeling by modulating collagen deposition and fibrosis. OPN, a multifunctional protein, has the potential to influence the molecular and cellular changes associated with infarct healing. The post-MI infarct healing process involves temporarily overlapping phases that include the following--(1) inflammation with migration and adhesion of neutrophils and macrophages, phagocytosis and inflammatory gene expression; (2) tissue repair with fibroblast adhesion and proliferation, myofibroblast differentiation, extracellular matrix deposition and scar formation; and (3) structural and functional remodeling of infarcted and non-infarcted myocardium through cardiac myocyte apoptosis, hypertrophy and myocardial angiogenesis. This review is focused on the expression of OPN in the heart post MI and its role in various phases of infarct healing.