title: Stimulation of osteoclast formation by inflammatory synovial fluid.
abstract: Peri-articular bone resorption is a feature of arthritis due to crystal deposition and rheumatoid disease. Under these conditions, the synovial fluid contains numerous inflammatory cells that produce cytokines and growth factors which promote osteoclast formation. The aim of this study was to determine whether inflammatory synovial fluid stimulates the formation of osteoclasts. Synovial fluid from rheumatoid arthritis (RA), pyrophosphate arthropathy (PPA) and osteoarthritis (OA) patients was added to cultures (n=8) of human peripheral blood mononuclear cells (PBMCs) in the presence and absence of macrophage colony-stimulating factor (M-CSF) and the receptor activator of NF-kappaB ligand (RANKL). Osteoclast formation was assessed by the formation of cells positive for tartrate-resistant acid phosphatase (TRAP) and vitronectin receptor (VNR) and the extent of lacunar resorption. The addition of 10% OA, RA and PPA synovial fluid to PBMC cultures resulted in the formation of numerous multinucleated or mononuclear TRAP(+) and VNR(+) cells which were capable of lacunar resorption. In contrast to PBMC cultures incubated with OA synovial fluid, there was marked stimulation of osteoclast formation and resorption in cultures containing inflammatory RA and PPA synovial fluid which contained high levels of tumour necrosis factor alpha, a factor which is known to stimulate RANKL-induced osteoclast formation.
authors.affiliation: Institute of Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Oxford, UK.
authors.forename: Iannis E
authors.initials: IE
authors.lastname: Adamopoulos
authors.forename: Lynett
authors.initials: L
authors.lastname: Danks
authors.forename: Ichiro
authors.initials: I
authors.lastname: Itonaga
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Locklin
authors.forename: Afsie
authors.initials: A
authors.lastname: Sabokbar
authors.forename: David J P
authors.initials: DJ
authors.lastname: Ferguson
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Athanasou
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000368:Aged; D001168:Arthritis / Q000378:metabolism* / Q000473:pathology; D001862:Bone Resorption / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010010:Osteoclasts / Q000378:metabolism* / Q000473:pathology; D013582:Synovial Fluid / Q000166:cytology / Q000378:metabolism*; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D039302:Integrin alphaVbeta3; D007527:Isoenzymes; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase