BMPs in periprosthetic tissues around aseptically loosened total hip implants.
OBJECTIVE
Primary and dynamically maintained periprosthetic bone formation is essential for osseointegration of hip implants to host bone. Bone morphogenetic proteins (BMPs) play a role in osteoinductive bone formation. We hypothesized that there is an increased local synthesis of BMPs in the synovial membrane-like interface around aseptically loosened total hip replacement (THR) implants, as body attempts to generate or maintain implant fixation.


METHODS
We compared synovial membrane-like interface tissue from revised total hip replacements (rTHR, n = 9) to osteoarthritic control synovial membrane samples (OA, n = 11. Avidin-biotin-peroxidase complex staining and grading of BMP-2, BMP-4, BMP-6, and BMP-7 was done. Immunofluorescence staining was used to study BMP proteins produced by mesenchymal stromal/stem cells (MSCs) and osteoblasts.


CONCLUSIONS
All BMPs studied were present in the synovial lining or lining-like layer, fibroblast-like stromal cells, interstitial macrophage-like cells, and endothelial cells. In OA and rTHR samples, BMP-6 positivity in cells, inducible by the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta, predominated over expression of other BMPs. Macrophage-like cells positive for BMP-4, inducible in macrophages by stimulation with particles, were more frequent around loosened implants than in control OA samples, but apparently not enough to prevent loosening. MSCs contained BMP-2, BMP-4, BMP-6, and BMP-7, but this staining diminished during osteogenesis, suggesting that BMPs are produced by progenitor cells in particular, probably for storage in the bone matrix.
Mikkeli Central Hospital, Mikkeli, Finland.
Ville
V
Waris
Eero
E
Waris
Tarvo
T
Sillat
Yrjö T
YT
Konttinen
D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D055396:Bone Morphogenetic Protein 2 / Q000096:biosynthesis / Q000502:physiology; D055415:Bone Morphogenetic Protein 4 / Q000096:biosynthesis / Q000502:physiology; D055418:Bone Morphogenetic Protein 6 / Q000096:biosynthesis / Q000502:physiology; D055419:Bone Morphogenetic Protein 7 / Q000096:biosynthesis / Q000502:physiology; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis / Q000502:physiology*; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D016348:Osseointegration / Q000502:physiology; D015207:Osteoarthritis, Hip / Q000378:metabolism / Q000601:surgery; D010006:Osteoblasts / Q000378:metabolism; D011475:Prosthesis Failure; D017154:Stromal Cells / Q000378:metabolism; D013583:Synovial Membrane / Q000378:metabolism
D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055418:Bone Morphogenetic Protein 6; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins