Circulating bone marrow osteoclast precursors and osteoclastogenesis in patients with type IIA and IIB hyperlipidemias.

Osteoclasts, the major source of calcium released during bone resorption, and their precursors preosteoclasts derive from bone marrow hemopoietic stem cells, granulocyte-macrophage colony-forming units. The factors responsible for commitment of colony-forming units into osteoclast precursors remain unknown. Studies of osteoclastogenesis in cultured blood mononuclear cells from patients with hyperlipidemia accompanied by atherosclerosis and calcification of vessels revealed high content of preosteoclasts in the blood.