title: Low IGF-I in synovial fluid and serum in patients with aseptic prosthesis loosening.
abstract: BACKGROUND
  We have previously shown that proliferation in primary cultures of human osteoblast-like cells is lower after exposure to synovial fluid from patients with aseptic prosthesis loosening than after exposure to synovial fluid from patients with osteoarthrosis.
  
  
  METHODS
  Insulin-like growth factors (IGF) I and II and IGF binding proteins (IGFBP) 3-6, were measured with radioimmunoassy in synovial fluid and in serum from patients with aseptic prosthesis loosening or osteoarthrosis. Proliferation in osteoblast-like MG-63 cells was studied with the CyQUANT assay.
  
  
  RESULTS
  IGF-I and IGFBP-4 concentrations were lower whereas the concentration of IGFBP-6 was higher in synovial fluids from patients with prosthesis loosening than in synovial fluid from patients with osteoarthrosis. IGF-I concentrations in serum from patients with prosthesis loosening were also lower than in the osteoarthrosis group, and were even below the normal range in most cases (72%). Synovial fluid from patients with aseptic loosening had a weaker stimulatory effect on MG63 osteoblast-like cell proliferation than synovial fluid from patients with osteoarthrosis, but there was no difference between the two groups when a human IGF-I antibody was added.
  
  
  CONCLUSIONS
  Low levels of IGF-I in synovial fluid possibly result from low serum levels and may be a mechanism leading to aseptic prosthesis loosening.
authors.affiliation: Department of Orthopaedic Surgery, Karolinska University Hospital Solna, Sweden.
authors.forename: Martin K
authors.initials: MK
authors.lastname: Andersson
authors.forename: André
authors.initials: A
authors.lastname: Stark
authors.forename: Lucas
authors.initials: L
authors.lastname: Anissian
authors.forename: Subburaman
authors.initials: S
authors.lastname: Mohan
authors.forename: Jon A
authors.initials: JA
authors.lastname: Tsai
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D049109:Cell Proliferation; D002478:Cells, Cultured; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins / Q000032:analysis* / Q000097:blood / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000502:physiology; D007335:Insulin-Like Growth Factor II / Q000032:analysis*; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000097:blood / Q000378:metabolism* / Q000601:surgery; D010006:Osteoblasts / Q000502:physiology; D011475:Prosthesis Failure; D012086:Reoperation; D013582:Synovial Fluid / Q000737:chemistry*
chemical_list: D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II