title: Bone marrow adipocytes support dexamethasone-induced osteoclast differentiation.
abstract: The purpose of this study was to examine the ability of bone marrow adipocytes to support osteoclast differentiation in vitro. The primary bone marrow adipocytes were obtained from bone marrow fluid during prosthesis insertion. NFkappa-B ligand (RANKL), Osteoprotegerin (OPG), and macrophage colony stimulating factor (M-CSF) expressions in bone marrow adipocytes with or without dexamethasone were examined. In a co-culture system with bone marrow adipocytes and osteoclast precursor cells, osteoclast differentiation was assessed by the expression of titrate-resistant acid phosphatase (TRAP) staining. RANKL, OPG, and M-CSF mRNA expressions were confirmed in all individuals. Dexamethasone significantly induced RANKL and OPG expression. The RANKL/OPG ratio was increased by dexamethasone and was significant at 10(-7) M dexamethasone. With 10(-7) M dexamethasone, osteoclast precursor cells differentiated into multinucleated TRAP-positive cells when co-cultured with bone marrow adipocytes. The present study demonstrates for the first time that bone marrow adipocytes can support osteoclast differentiation in vitro.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Hozumi
authors.forename: Makoto
authors.initials: M
authors.lastname: Osaki
authors.forename: Hisataka
authors.initials: H
authors.lastname: Goto
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Shigeru
authors.initials: S
authors.lastname: Inokuchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shindo