ADAMs, Osteoclastogenesis and Bone Destruction in the Loosening of the Totally Replaced Hip

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dc.contributor Helsingin yliopisto, lääketieteellinen tiedekunta, biolääketieteen laitos fi
dc.contributor Helsingfors universitet, medicinska fakulteten, biomedicinska institutionen sv
dc.contributor University of Helsinki, Faculty of Medicine, Institute of Biomedicine en
dc.contributor ORTON Orthopedic Hospital of the Invalid Foundation en
dc.contributor the Department of Anatomy. en Ma, Guofeng fi 2010-11-25T11:16:44Z 2010-11-25T11:16:44Z 2009-02-06 fi
dc.identifier.uri URN:ISBN:978-952-9657-47-6 fi
dc.description.abstract Total hip replacement is the golden standard treatment for severe osteoarthritis refractory for conservative treatment. Aseptic loosening and osteolysis are the major long-term complications after total hip replacement. Foreign body giant cells and osteoclasts are locally formed around aseptically loosening implants from precursor cells by cell fusion. When the foreign body response is fully developed, it mediates inflammatory and destructive host responses, such as collagen degradation. In the present study, it was hypothesized that the wear debris and foreign body inflammation are the forces driving local osteoclast formation, peri-implant bone resorption and enhanced tissue remodeling. Therefore the object was to characterize the eventual expression and the role of fusion molecules, ADAMs (an abbreviation for A Disintegrin And Metalloproteinase, ADAM9 and ADAM12) in the fusion of progenitor cells into multinuclear giant cells. For generation of such cells, activated macrophages trying to respond to foreign debris play an important role. Matured osteoclasts together with activated macrophages mediate bone destruction by secreting protons and proteinases, including matrix metalloproteinases (MMPs) and cathepsin K. Thus this study also assessed collagen degradation and its relationship to some of the key collagenolytic proteinases in the aggressive synovial membrane-like interface tissue around aseptically loosened hip replacement implants. ADAMs were found in the interface tissues of revision total hip replacement patients. Increased expression of ADAMs at both transcriptional and translational levels was found in synovial membrane-like interface tissue of revision total hip replacement (THR) samples compared with that in primary THR samples. These studies also demonstrate that multinucleate cell formation from monocytes by stimulation with macrophage-colony stimiulating factor (M-CSF) and receptor activator of nuclear factor kappa B ligand (RANKL) is characterized by time dependent changes of the proportion of ADAMs positive cells. This was observed both in the interface membrane in patients and in two different in vitro models. In addition to an already established MCS-F and RANKL driven model, a new virally (parainfluenza 2) driven model (of human salivary adenocarcinoma (HSY) cells or green monkey kidney (GMK) cells) was developed to study various fusion molecules and their role in cell fusion in general. In interface membranes, collagen was highly degraded and collagen degradation significantly correlated with the number of local cells containing collagenolytic enzymes, particularly cathepsin K. As a conclusion, fusion molecules ADAM9 and ADAM12 seem to be dynamically involved in cell-cell fusion processes and multinucleate cell formation. The highly significant correlation between collagen degradation and collagenolytic enzymes, particularly cathepsin K, indicates that the local acidity of the interface membrane in the pathologic bone and soft tissue destruction. This study provides profound knowledge about cell fusion and mechanism responsible for aseptic loosening as well as increases knowledge helpful for prevention and treatment. en
dc.description.abstract The formation of multinucleated cells such as myotubes, macrophage-derived giant cells and osteoclasts is the result of cell-cell fusion of mononuclear precursors. The ADAMs (an acronym for A Disintegrin And Metalloproteinase) is a family of multifunctional proteins that exhibit a significant similarity with snake venom metalloproteases and are involved in cell-cell fusion processes. As fusion molecules, ADAM12 and ADAM9 are involved in cell-cell fusion processes and participate in myoblast fusion and, also in osteoclast fusion. The aims of the proposed project are to characterize ADAMs expression and regulations both in the interface membrane of total hip replacement in the patients and in in vitro cell model. Further study of the relationship between the structure and function of ADAMs may provide profound knowledge of its role in cell fusion, and even one attractive therapeutic target. fi
dc.language.iso en fi
dc.publisher Helsingin yliopisto fi
dc.publisher Helsingfors universitet sv
dc.publisher University of Helsinki en
dc.relation.isformatof URN:ISBN:978-952-9657-46-9 fi
dc.relation.isformatof Helsinki: 2009, 1455-1330 fi
dc.rights Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty. fi
dc.rights This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited. en
dc.rights Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden. sv
dc.subject lääketiede fi
dc.title ADAMs, Osteoclastogenesis and Bone Destruction in the Loosening of the Totally Replaced Hip en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.type.ontasot Doctoral dissertation (article-based) en
dc.type.ontasot Doktorsavhandling (sammanläggning) sv
dc.ths Konttinen, Yrjö fi
dc.ths Salo, Jari fi
dc.opn Tuukkanen, Juha fi
dc.type.dcmitype Text fi

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