Table 1. Role of essential cells implicated in osteolysis pathogenesis.
Cell type | Role | Comments |
---|---|---|
Monocyte/macrophage | Dominant cell type implicated in osteolysis: vastly present in periprosthetic tissue and pseudosynovial membrane, and correlated with bone resorption5–8,22,28–31 Secrete MMPs, TNF-α, IL-1β, IL-6, and eicosanoids after phagocytosis of wear debris101 Systemic migration contributes to local infiltration, osteoclast differentiation, and bone destruction28 Increased peripheral CD14+CD16+ phenotype frequency; correlated with increased baseline level and production of TNF-α and IL-1β52 | Potent, proinflammatory phenotype |
Dendritic cell | Infiltrate and surround UHMWPE particles, participating in phagocytosis and MGC formation7,42,44 Produce proinflammatory cytokines IL-1, IL-6, IL-12, TNF-α, and IFN-γ 7,42,44,46 Compose prosthetic synovial pseudomembrane7 | Ultimately results in NALP3 inflammasome activation and enzymatic bone resorption; likely paralleling macrophage function Contributes to osteoclastogenesis and activation |
Osteoblast | Able to phagocytose wear particles and alter cellular signaling6,102 Decrease OPG secretion when challenged with PE in vitro103 Express RANKL104 and M-CSF105 upon TNF-α and IL-1β stimulation in vitro Dose-dependent decrease in proliferation, differentiation, and mineralization when challenged with UHMWPE particles in vitro102 Decreased expression of procollagen α1 mRNA and synthesis of collagen I in vitro by phagocytic- dependent and -independent mechanisms when challenged with PE particles101 Increased expression of IL-6101 and IL-8103 when challenged with PE in vitro | |
Fibroblast | Present in pseudosynovial periprosthetic membrane9,40 Expresses RANKL and can induce osteoclast differentiation in pseudosynovial membrane106 Activated by TNF-α and IL-1β and produce MMPs and cytokines in titanium wear107 and osteoarthritis108 models In tissues exposed to PE, possess MMP2 mRNA alongside macrophages and MGCs expressing MMPs 2 and 14 protein but only MMP14 mRNA109 | Likely activated by TNF-α and IL-1β in presence of PE as well, contributing to inflammation Suggests cooperation with macrophages in local tissue destruction |
IL-1, interleukin-1; IFN-γ, interferon-γ; M-CSF, macrophage colony-stimulating factor; MGC, multinucleated giant cell; MMP, matrix metalloproteinase; OPG, osteoprotegerin; PE, polyethylene; RANKL, receptor activator of nuclear factor-κB ligand; TNF-α, tumor necrosis factor-α; UHMWPE, ultra-high molecular weight polyethylene.