Circulating Osteoblast-Lineage Cells in Humans

• Published in: The New England journal of medicine Vol. 352; no. 19; pp. 1959 - 1966
• Main Authors: Eghbali-Fatourechi, Guiti Z, Lamsam, Jesse, Fraser, Daniel, Nagel, David, Riggs, B. Lawrence, Khosla, Sundeep
• Format: Journal Article
• Language: English
• Published: Boston, MA Massachusetts Medical Society 12.05.2005
• Subjects: Adolescent; Adult; Aging - physiology; Alkaline Phosphatase - blood; Alkaline Phosphatase - genetics; Alkaline Phosphatase - immunology; Animals; Biological and medical sciences; Bone marrow; Bone Remodeling - physiology; Cell Lineage; Collagen Type II - blood; Collagen Type II - genetics; Flow Cytometry; Fractures, Bone - blood; Gene Expression; General aspects; Genetic Markers; Humans; Immunoassay; Immunocompromised Host; Insulin-Like Growth Factor I - analysis; Insulin-like growth factors; Male; Medical sciences; Mice; Middle Aged; Osteoblasts; Osteocalcin - blood; Osteocalcin - genetics; Osteocalcin - immunology; Osteogenesis - physiology; Reverse Transcriptase Polymerase Chain Reaction; Studies; Human; Medicine; Osteoblast; Cell lineage
• ISSN: 0028-4793; 1533-4406; 1533-4406
• DOI: 10.1056/NEJMoa044264

Circulating osteoblast-lineage cells have been considered rare. This study used new methods to show that osteoblastic cells are present in large numbers in peripheral blood in adult men. Furthermore, the concentration of cells increases markedly in adolescent boys during pubertal growth and in adult men after fractures. Thus, osteoblast-lineage cells circulate in physiologically significant numbers, possibly representing a previously unrecognized circulatory component of the process of bone formation. This study used new methods to show that osteoblastic cells are present in large numbers in peripheral blood in adult men. The concentration of cells increases markedly in adolescent boys during pubertal growth and in adult men after fractures. Bone marrow contains both osteoblast and osteoclast precursors that can differentiate into the mature osteoblasts and osteoclasts, respectively, 1 that are believed to be needed for normal bone remodeling on trabecular surfaces contiguous to bone marrow. In addition to residing in the bone marrow, substantial numbers of osteoclast precursors are detectable in the peripheral circulation, 2 and these cells may be able to travel to sites of active bone remodeling distant from red marrow. However, it is unclear whether a parallel process involving circulating osteoblast-lineage cells exists and, if so, what role these osteoblastic cells might play in normal or pathologic bone . . .