Osteopontin in Vascular Disease.

Inflammatory cytokines are necessary for an acute response to injury and the progressive healing process. However, when this acute response does not resolve and becomes chronic, the same proteins that once promoted healing then contribute to chronic inflammatory pathologies, such as atherosclerosis. OPN (Osteopontin) is a secreted matricellular cytokine that signals through integrin and CD44 receptors, is highly upregulated in acute and chronic inflammatory settings, and has been implicated in physiological and pathophysiologic processes.

Osteopontin isoforms differentially promote arteriogenesis in response to ischemia via macrophage accumulation and survival.

Osteopontin (OPN) is critical for ischemia-induced neovascularization. Unlike rodents, humans express three OPN isoforms (a, b, and c); however, the roles of these isoforms in post-ischemic neovascularization and cell migration remain undefined. Our objective was to determine if OPN isoforms differentially affect post-ischemic neovascularization and to elucidate the mechanisms underlying these differences.

Alkaptonuria-associated aortic stenosis.

Alkaptonuria is an autosomal recessive disorder of tyrosine metabolism, which results in accumulation of unmetabolized homogentisic acid and its oxidized product in various tissues, including the heart. Cardiovascular involvement is a rare but serious complication of the disease. We present two patients who have undergone successful aortic valve replacement for alkaptonuria-associated aortic stenosis along with a review of the literature.