BONE MORPHOGENETIC PROTEIN EXPRESSION IN HUMAN ATHEROSCLEROTIC LESIONS

Artery wall calcification associated with atherosclerosis frequently c ontains fully formed bone tissue including marrow. The cellular origin is not known. In this study, bone morphogenetic protein-2a, a potent factor for osteoblastic differentiation, was found to be expressed in calcified human atherosclerotic plaque. In addition, cells cultured fr om the aortic wall formed calcified nodules similar to those found in bone cell cultures and expressed bone morphogenetic protein-2a with pr olonged culture. The predominant cells in these nodules had immunocyto chemical features characteristic of microvascular pericytes that are c apable of osteoblastic differentiation. Pericyte-like cells were also found by immunohistochemistry in the intima of bovine and human aorta. These findings suggest that arterial calcification is a regulated pro cess similar to bone formation, possibly mediated by pericyte-like cel ls.