Macrophage-osteoclast differentiation and bone resorption in osteoarthrotic subchondral acetabular cysts.
A macrophage infiltrate is commonly found in enlarging subchondral cysts in osteoarthrosis (OA) and the surrounding bone. To determine whether osteoclast differentiation by these cells contributes to the increase in the number of osteoclasts and bone resorption that accompanies OA cyst enlargement, we isolated macrophages from the wall of OA cysts and co-cultured them with osteoblast-like UMR106 cells in the presence or absence of 1,25(OH)2D3 and M-CSE After 14 days of incubation, co-cultures of UMR106 cells and cyst-derived macrophages showed evidence of osteoclast differentiation by expression of TRAP, VNR and formation of numerous lacunar pits. We found that, unlike osteoclast precursors in monocyte and other tissue macrophage populations, the addition of M-CSF to medium is not required for osteoclast differentiation. Our findings suggest that macrophage-osteoclast differentiation is one means whereby the osteolysis associated with the enlargement of OA cysts could be effected.
Nuffield Department of Orthopaedic Surgery, Nuffield Orthopaedic Centre, Oxford, UK.
A
A
Sabokbar
R
R
Crawford
D W
DW
Murray
N A
NA
Athanasou
D000077:Acetabulum / Q000473:pathology; D000135:Acid Phosphatase / Q000032:analysis; D000368:Aged; D001845:Bone Cysts / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D001862:Bone Resorption / Q000150:complications / Q000473:pathology*; D002117:Calcitriol / Q000494:pharmacology; D002454:Cell Differentiation; D018920:Coculture Techniques; D005260:Female; D005270:Femur Head / Q000473:pathology; D006801:Humans; D007527:Isoenzymes / Q000032:analysis; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D016177:Macrophage-1 Antigen / Q000032:analysis; D008264:Macrophages / Q000737:chemistry / Q000166:cytology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000150:complications / Q000473:pathology*; D010010:Osteoclasts / Q000737:chemistry / Q000166:cytology / Q000473:pathology*; D019030:Receptors, Vitronectin / Q000032:analysis; D000071681:Tartrate-Resistant Acid Phosphatase
D007527:Isoenzymes; D016177:Macrophage-1 Antigen; D019030:Receptors, Vitronectin; D016173:Macrophage Colony-Stimulating Factor; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D002117:Calcitriol