title: High macrophage-colony stimulating factor levels in synovial fluid of loose artificial hip joints.
abstract: OBJECTIVE
  To clarify a macrophage-colony stimulating factor (M-CSF) related mechanism of aseptic loosening of artificial hip joints.
  
  
  METHODS
  Synovium-like interface tissues between bone and prosthesis, regenerated pseudocapsular tissues, and synovial fluid (SF) were collected from 9 patients with loose artificial hip joint at revision surgery. Tissue distribution, production site, and SF level of M-CSF in loose hip joints were investigated by immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR), and ELISA, respectively. For a comparative assessment of the M-CSF level in loose hip joints, SF of active rheumatoid arthritis (RA) and mild osteoarthritis (OA) also were analyzed by ELISA.
  
  
  RESULTS
  Immunohistochemical analysis showed the presence of M-CSF immunoreactive cells mainly in the interface tissues between bone and prosthesis and inner pseudocapsular tissues, both of which were in contact with joint fluid. RT-PCR analysis confirmed the local production of M-CSF in these periprosthetic tissues. Significantly higher M-CSF level in loose hip joint fluid than in active RA and mild OA fluid was revealed by ELISA.
  
  
  CONCLUSIONS
  High M-CSF level in loose hip joint fluid suggests transportation of M-CSF from production sites to joint fluid. This indicates that not only polyethylene wear particles (reported to induce foreign body reaction at the bone-prosthesis interface), but also M-CSF, abundant in joint fluid, are transported to and affect the interface. Thus, M-CSF is locally produced in periprosthetic tissues of loose hip joints and possibly contributes to periprosthetic weakening and osteolysis via joint fluid, leading to prosthetic loosening.
authors.affiliation: Department of Orthopedic Surgery, Yamagata University School of Medicine, Japan. itakei@med.id.yamagata-u.ac.jp
authors.forename: I
authors.initials: I
authors.lastname: Takei
authors.forename: M
authors.initials: M
authors.lastname: Takagi
authors.forename: H
authors.initials: H
authors.lastname: Ida
authors.forename: T
authors.initials: T
authors.lastname: Ogino
authors.forename: S
authors.initials: S
authors.lastname: Santavirta
authors.forename: Y T
authors.initials: YT
authors.lastname: Konttinen
mesh_terms: D000368:Aged; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015870:Gene Expression / Q000276:immunology; D006622:Hip Prosthesis; D006801:Humans; D007150:Immunohistochemistry; D007593:Joint Instability / Q000276:immunology / Q000378:metabolism*; D016173:Macrophage Colony-Stimulating Factor / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008264:Macrophages / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000737:chemistry / Q000378:metabolism; D015207:Osteoarthritis, Hip / Q000276:immunology / Q000378:metabolism / Q000601:surgery; D010014:Osteolysis / Q000276:immunology / Q000378:metabolism; D011475:Prosthesis Failure; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013582:Synovial Fluid / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D016173:Macrophage Colony-Stimulating Factor