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Identification of macrophage migration inhibitory factor in synovial membranes of loosened total joint replacement
K Suzuki1, S Onodera, T Matsuno
1Department of Orthopedic Surgery, Hokkaido University School of Medicine, Japan.
Abstract:
Endosteal bone resorption often occurs around loosened total joint replacements. In the process of the loosening, macrophages play an important role by releasing cytokines such as interleukin-1, tumor necrosis factor-alpha and prostaglandin E2. In this study, we investigated the involvement of macrophage migration inhibitory factor (MIF) in the pathological state of the loosening of a total hip replacement. Interface membranes were harvested from bone-cement or bone-implant interfaces of two patients during revision hip surgeries. The tissues were immunohistochemically examined with a polyclonal antibody against human recombinant MIF. This study detected MIF in the cytoplasm of the macrophages in all the tissues tested, though it was not detected in that of interstitial cells. The expression of MIF mRNA in the membrane was also examined by reverse transcription polymerase chain reaction, which demonstrated that expression of the MIF mRNA in the interface membranes was higher than that of the normal synovium. Considering these results, it is suggested that MIF is one of important cytokines mediating the inflammatory process during loosening of total joint replacements.
Insights
Macrophage migration inhibitory factor (MIF) is present in tissues surrounding loosened hip replacements. This finding suggests MIF plays a role in the inflammation associated with joint replacement loosening.
Area of Science:
- Biomedical Engineering
- Immunology
- Orthopedic Surgery
Background:
- Endosteal bone resorption is a common issue around loosened total joint replacements.
- Macrophages and their released cytokines (IL-1, TNF-α, PGE2) are key players in this loosening process.
Purpose of the Study:
- To investigate the role of macrophage migration inhibitory factor (MIF) in the pathological loosening of total hip replacements.
Main Methods:
- Interface membranes from revision hip surgeries were immunohistochemically analyzed for MIF.
- MIF mRNA expression in these membranes was quantified using reverse transcription polymerase chain reaction (RT-PCR).
Main Results:
- MIF was detected in the cytoplasm of macrophages within the interface membranes.
- MIF mRNA expression was significantly higher in interface membranes compared to normal synovium.
Conclusions:
- MIF is implicated as an important cytokine in the inflammatory processes driving total joint replacement loosening.
- Further research into MIF's role could lead to new therapeutic strategies for joint replacement failure.